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Volume 79, 1951
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Studies on the Earthworm Fauna of New Zealand—II

[Read before the Wellington Branch, May 30, 1951; received by the Editor, May 30, 1951]

All the known species of the endemic earthworm fauna of New Zealand belong to the family Megascolecidae, and within that family to the three sub-families Acanthodrilinae, Megascolecinae and Octochaetinae. It is with the last of the three sub-families, the Octochaetinae, that this paper is concerned.

The present definition of the sub-family was set down by Stephenson (1915). As set out by this author in his monograph (1930, p. 841) it runs:

“Arrangement of chaetae from pure lumbricine to pure perichaetine. One oesophageal gizzard in one simple segment, or two in two simple segments, or one in a space which represents two or more fused segments; in the last two cases calciferous glands in the region of x–xiii. Excretory system of meganephridia along with micronephridia, or micronephridia alone, the latter never having the form of sacs. Sexual apparatus from pure acanthodriline to pure microscolescine.

Distribution: Throughout India, but more sparsely in the north; New Zealand; South Madagascar.”

The distribution of the sub-family, particularly the genus Octochaetus, which is found in India and New Zealand, has been widely discussed by biologists. Michaelsen (1921) considered that there must have been a continuous land bridge between India and New Zealand, not passing through Australia, at some time in the past, allowing Octochaetus to achieve its distribution. The postulation of such a land bridge, however, raises obvious difficulties, since if it had existed one would expect to find closer affinities between other elements of the present faunae of India and New Zealand. Michaelsen (1921) split the genus, mainly on geographical grounds, into two sub-genera, O. Octochaetus for the New Zealand species and O. Octochaetoides for the Indian species. Stephenson (1923) suggested that the two sub-genera may be quite distinct and may have evolved separately in the two regions, but in 1930 (p. 844) he allowed the two sub-genera to stand. It seems to the present author that Stephenson's opinion of 1923 gives the most reasonable explanation of the problem. The only essential difference between Octochaetus and a typical “acanthodriline” genus of the sub-family Acanthodrilinae is that the former has a micronephridial excretory system while the latter has a meganephridial excretory system. There is a common tendency throughout the family Megascolecidae for a change from the meganephridial to the micronephridial condition (e.g. in Megascolides and Spenceriella meganephridia and micronephridia frequently are found in the same species) and there is no reason why such a change should not have

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taken place in some New Zealand Acanthodriline genus, giving rise to a genus having the same characters as the Indian genus Octochaetoides. Evidence that such a change can occur in an Acanthodriline genus is found in Rhododrilus disparatus Lee, a species having all the characters of the genus Rhododrilus except that in ii–xx micronephridia are present together with meganephridia.

Five genera belonging to the sub-family Octochaetinae have been recorded from New Zealand. They are:

  • Octochaetus Beddard (1892)

  • Dinodrilus Beddard (1890)

  • Hoplochaetina Michaelsen

  • Conicodrilus Benham (1945)

  • Cryptochaeta Benham (1950)

To these five genera must be added Leucodrilus n.g., described in this paper.

The three genera Octochaetus, Dinodrilus and Hoplochaetina may mark three stages in an evolutionary trend, since they each have the acanthodriline arrangement of the reproductive organs and have respectively eight, twelve, and more than twelve chaetae on each segment. Leucodrilus is similar to Octochaetus except that it has the microscolecine arrangement of the reproductive organs. It might be said that Leucodrilus is then synonymous with the Indian genus Eudichogaster, but since it is apparent that the New Zealand Octochaetinae are distinct from the Indian group, Leucodrilus must be regarded as a genus distinct from Eudichogaster. Here must again be mentioned Rhododrilus disparatus, which by its possession of micronephridia in association with meganephridia in the anterior segments could be included in Leucodrilus. However, as its relationships lie more closely with Rhododrilus, it is better that it should be left in that genus. It does show how Leucodrilus could have been derived independently from the Acanthodrilinae and not necessarily from Octochaetus by the supervention of the microscolecine condition of the reproductive organs.

The genus Conicodrilus was established by Benham in 1945 for species which resemble Dinodrilus in all respects except that the prostatic papillae of Conicodrilus take the form of prominent, relatively long, pointed cones as opposed to the more usual low, rounded prostatic papillae generally found in Dinodrilus. Benham took as the type of his genus Dinodrilus gracilis Ude (1905), which he placed in the new genus together with Conicodrilus kanieriensis Benham (1945). The form of the prostatic papillae varies widely in many genera of earthworms, e.g. in Rhododrilus, one species (R. aduncocystis) has no prostatic papillae, each pore merely opening in the centre of a small brownish area on the ventral aspect of xvii, while in other species of Rhododrilus (e.g. R. macroseptus) the prostatic papillae are prominent dome-like structures. If Benham's differentiation of Conicodrilus and Dinodrilus on the form of the prostatic papillae is accepted, then R. aduncocystis must be differentiated as a new genus although it has all the characters of Rhododrilus. In many other cases new genera would have to be established. Such

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a situation would present many difficulties, and to preserve some degree of uniformity Conicodrilus should go back into Dinodrilus.

Cryptochaeta is a genus established by Benham (1950) for a species, C. microchaeta, which resembles Octochaetus in all respects except that the chaetae are arranged in four very closely spaced couples on each segment, instead of the generally widely spaced chaetae of Octochaetus. Now, according to Stephenson's definition of Octochaetus (1930) the chaetae are lumbricine in arrangement. The same author (1930, p. 13) defines the lumbricine arrangement of the chaetae as follows: “lumbricine—eight chaetae per segment, usually arranged in pairs as in Lumbricus; sometimes, however, they are not paired, the interval between the two chaetae of the dorsal couple, or of both dorsal and ventral couples, being as great as that between the ventral and the dorsal couples.” In other words, provided there are eight chaetae on each segment, the arrangement is lumbricine, regardless of the spacing of the individual chaetae. If spacing of the chaetae is taken as a character of generic importance, most, if not all, genera of earthworms would have to be split and once again a confusing situation would arise. So Cryptochaeta should be included in Octochaetus and C. microchaeta should become O. microchaetus.

There are, then, four genera of the sub-family known from New Zealand. The relationships of these genera are probably best expressed in the following diagram, taking as a root genus the “Notodrilus” ancestor of the whole family Megascolecidae:

Rhododrilus does not belong to the sub-family Octochaetinae, but is included in the diagram as a possible root genus for Leucodrilus.

The New Zealand genera of the sub-family Octochaetinae may be identified from the following key:

a1 One pair of prostatic pores on xvii Leucodrilus
a2 Two pairs of prostatic pores, on xvii and xix
b1 Eight chaetae on each segment Octochaetus
b2 Twelve chaetae on each segment Dinodrilus
b3 More than twelve chaetae on each segment Hoplochaetina

Genus Octochaetus

“Chaetae with lumbricine arrangement. One oesophageal gizzard in one simple segment; calciferous glands in the region of xv–xvii. Purely micronephridial. Sexual apparatus purely acanthodriline.” (Stephenson, 1930).

Including O. (Cryptochaeta) microchaetus, five species (and one doubtful species) of this genus have been reported from New Zealand by previous workers. These species are:

  • O. multiporus Beddard (1892)

  • O. thomasi Beddard (1892)

  • O. huttoni Beddard (1892)

  • O. michaelseni Benham (1904)

  • O. microchaetus Benham (1950)

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and the doubtful species O. levis (Hutton, 1876). To these must now be added the three new species O. sylvestris, O. tricystis and O. brucei, described in this paper.

O. levis was described by Hutton as Lumbricus levis and the type specimen was re-examined by Benham (1898) and placed in the genus Octochaetus. When re-examined by Benham the type was in a poor state of preservation and could only be identified as “a species of Octochaetus.”

O. multiporus and O. thomasi are very similar species, their principal point of difference being that O. multiporus is a very large species while O. thomasi is rather small.

A species described by Beddard (1890) under the name of Acanthodrilus antarcticus must be mentioned here. This species was included by Ude (1905) in the genus Octochaetus as O. antarcticus. Since Beddard's original description makes no mention of the form of nephridia found in this species and the only difference between Octochaetus and Acanthodrilus (or, for that matter, Maoridrilus) is in the form of the nephridia, it must remain as a “species incertae sedis.”

The New Zealand species of Octochaetus (except O. levis) may be identified from the following key:

a1 One pair of calciferous glands in xv
  b1, Intestine commencing in xvi O. michaelseni
  b2, Intestine commencing in xviii
    c1 Dorsal blood vessel paired throughout its length O. tricystis
    c2 Dorsal blood vessel unpaired anterior to septum
      vi/vii O. sylvestris
a2 One pair of calciferous glands in xvi O. brucei
a3 One pair of calciferous glands in xvii O. multiporous and O. thomasi
a4 Two pairs of calciferous glands in xv and xvi O. huttoni
a5 Three pairs of calciferous glands in xiii, xiv and xv O. microchaetus

The following are descriptions of the three new species O. tricystis, O. sylvestris and O. brucei. Type specimens in the author's collection.

Octochaetus tricystis n.sp. (Plate 115, figs. 1–3)

Several specimens of this new species were collected from Kiwitea loam in the R. C. Bruce Park, an area of virgin bush (matai, rimu, tawa and ngaio) situated a few miles south of Hunterville. The body is unpigmented except for the clitellum, which is purplish in colour and extends over the dorsal and lateral surfaces of xiv–xvii and the posterior portion of xiii. The specimen described below is 82 mm. long, 5 mm. in diameter, and has 94 segments.

The prostomium is prolobous. There are eight chaetae on each segment, arranged in pairs. On xxiv the arrangement of the chaetae is as follows:

ab = 1 mm.; cd = 1·5 mm.; aa = 2·5 mm.; bc = 2 mm.; dd = 5 mm.

There are two pairs of spermathecal pores, a pair at 7/8, and a pair at 8/9, in line with chaeta b. A pair of female pores occurs on xiv, a pore slightly anterior and medial to chaeta a on each side. There are two pairs of prostatic pores, a pair on xvii and a pair on xix, situated on rounded white papillae lateral to chaeta b. It is unusual for chaeta b to be present on the segments bearing the prostatic papillae, but in this species they do occur. A narrow groove, passing

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along a raised white ridge, joins the two prostatic pores of each side and the male pores lie, one on each side of the body, in these grooves lateral to chaeta b on xviii.

There are no nephridiopores. Dorsal pores commence at 8/9 and occur in each intersegmental groove posterior to 8/9.

Internal Anatomy (Plate 115, fig. 2)

The septa ix/x, x/xi, xi/xii and xii/xiii are muscular and thickened.

Alimentary Canal. There is a strongly muscular pharynx in i–iv. A thin-walled proventriculus lies in v and vi. It is much larger than is usually the case in the Megascolecidae. The proventriculus passes into a very thick-walled muscular gizzard which occupies vii. The oesophagus passes through viii–xvii and bears a single pair of prominent calciferous glands in xv. The intestine commences in xviii.

Vascular System. The dorsal blood vessel is paired throughout its length. A slender unpaired supra-intestinal blood vessel extends through x-xiii and gives rise to a pair of hearts in each of those segments.

Reproductive System. There are two pairs of testes, a pair in x and a pair in xi, attached to the anterior septum of each segment close to the ventral mid-line, and a pair of ovaries in a similar position in xiii. The testes and ovaries have a similar form, each organ consisting of a cluster of short, thread-like processes projecting freely into the coelomic cavity of the segment. There are two pairs of large spermathecae, a pair in viii and a pair in ix. Each consists of a large dorsoventrally flattened oval sac opening by a slender duct to the exterior. Three small diverticula open into the upper part of the duct close to the spermathecal sac (Plate 115, fig. 3). A pair of prostates lies in each of segments xvii and xix. The prostates are extremely convoluted tubular organs, each opening by a narrow muscular duct to the exterior. There are neither penial chaetae nor copulatory muscles in the prostatic segments. A pair of vesiculae seminales occurs in each of ix, x, xi and xii. Those of xi and xii are of a racemose form and occupy most of the coelomic cavity of the segments, while those of ix and × are more compact, smaller structures, attached to the posterior septa of their respective segments.

A band of small micronephridial tubules is found on the lateral aspect of the peritoneum on each side of each segment except the first.

Octochaetus sylvestris n.sp. (Plate 116, figs. 1–3)

A number of specimens of this light pink earthworm were collected from Kopua silt loam in an area of native rain-forest (rimu, matai, lancewood, rata) at Wakarara station, Central Hawke's Bay.

The specimen on which this description is based is 87 mm. in length and 4 mm. in diameter, with 154 segments.

The prostomium is tanylobous. The clitellum is buff in colour and prominent, covering the dorsal and lateral surfaces of segments xiii–xvii. The first six segments have no secondary annulations, but vii and all the segments posterior to vii are biannulate.

There are eight chaetae on each segment, arranged in pairs. On segment xxiv:

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ab = 1 mm.; cd = 1·25 mm.; aa = 1·5 mm.; be = 1·5 mm.; dd = 4·5 mm.

There are two pairs of spermathecal pores, at 7/8 and 8/9, in line with the chaetae ab. A single pair of female pores occurs on xiv slightly anterior to the chaeta a. There are two pairs of prostatic pores on xvii and xix, each pore situated on a small white papilla in line with the chaetae ab. A longitudinal groove joins the two prostatic pores of each side and the male pores lie in these grooves on xviii, between the chaetae a and b. There is a tuberculum pubertatis, in the form of a lateral ridge on the ventral surface of xvi, extending from chaeta b of one side to chaeta b of the other side. A similar tuberculum occurs on xx.

There are no nephridiopores. Dorsal pores commence at 17/18 and occur in every intersegmental groove posterior to this.

Internal Anatomy (Plate 116, fig. 2)

There are no specially thickened septa.

Alimentary Canal. The pharynx occupies the first four segments. There is a large, thick-walled gizzard in vi, connected to the pharynx by a short, thin-walled proventriculus. The oesophagus is narrow and extends from vii to xvii and has a prominent pair of calciferous glands in xv. The intestine commences in xviii, is thin walled and has a typhlosole.

Vascular System. The dorsal blood vessel is paired, but the two vesels fuse at septum vii/viii and remain fused anterior to that point. There are four pairs of dilated hearts in segments x, xi, xii and xiii.

Reproductive System. There are two pairs of testes in × and xi, and a single pair of ovaries in xiii. There are two pairs of spermathecae in viii and ix. Each is a large, round, laterally compressed sac opening to the exterior by a short, narrow duct. Two small diverticula, one anterior and one posterior, open into the proximal region of the duct. (Plate 116, Fig. 3.) Two pairs of convoluted prostates occur in xvii and xix, each prostate wholly confined to one segment. I can find no penial chaetae, and there is no sign of the copulatory muscles frequently found in the region of the prostates in the genus Octochaetus. There are two pairs of racemose vesiculae seminales in xi and xii.

Micronephridia commence in v. In that segment they form a cushion-like mass of long tubules on each side of the segment, but in the segments posterior to v the usual arrangement of a band of tubules on the lateral aspects of the peritoneum in each segment is found.

This species, in its external features and internal anatomy, shows very close resemblance to O. michaelseni (Benham, 1904). The dorsal blood vessel becomes paired at vii/viii, there is a prominent pair of calciferous glands in xv, there are two pairs of spermathecae, all characters shared with O. michaelseni, but the intestine of O. sylvestris commences in xviii while that of O. michaelseni commences in xvi, the spermathecae of O. xylvestris are rounded and have two very small diverticula opening into the medial aspect of the spermathecal duct while those of O. michaelseni are of an irregular bilobed form and

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appear to have no diverticula, and in other smaller points of external and internal anatomy the two species differ.

Octochaetus brucei n.sp. (Plate 117, figs. 1–3)

A single specimen of this species was obtained from Kiwitea loam under ngaio and tawa in the R. C. Bruce Park, a few miles south of Hunterville. It was light pink in colour and the clitellum was not obvious.

The species is 175 mm. in length and 9 mm. in diameter and has 431 segments. The segments are biannulate. The prostomium is prolobous. There are eight chaetae on each segment, arranged in four pairs, a pair in a ventral position and a pair in a ventro-lateral position on each side of each segment. On xxiv, the arrangement is as follows:

ab = cd = 0·25 mm.; bc = 3 mm.; aa = 4 mm.; dd = 17 mm.

There are two pairs of spermathecal pores, a pair at 7/8 and a pair at 8/9, in line with the chaetae ab. The female pores are on xiv, one on each side, anterior and slightly medial to chaeta a. There are two pairs of prostatic pores, a pair on xvii and a pair on xix, each pore opening at the apex of a low mound-like tumid area in line with the chaetae ab. A narrow groove joins the two prostatic pores of each side. This groove runs along the centre of a low tumid ridge joining the two prostatic papillae of each side and passes between the chaetae a and b on xviii. A male pore is situated in the groove on each side, between chaetae a and b on xviii. There are no tubercula pubertatis.

Dorsal pores commence at 19/20 and occur in every intersegmental groove posterior to 19/20. There are no nephridiopores.

Internal Anatomy (Plate 117, fig. 2)

The septa v/vi, vi/vii, vii/viii, viii/ix, ix/x, x/xi, xi/xii are very muscular and greatly thickened and the septa xii/xiii and xiii/xiv are slightly muscular and thickened.

Alimentary Canal. The pharynx occupies segments i–iv. A strongly muscular, thick-walled gizzard lies in v and the oesophagus extends from vi to xviii. There is a pair of dilated calciferous glands in xvi. The intestine commences in xix; it is wide and thin walled and has no typhlosole. The chloragogen tissue has an unusual form. It consists, in each of the segments posterior to xxii, of two slender lobes, attached to the walls of the intestine and extending up on to the dorso-lateral aspect of the intestine on each side, with a small dorsal gap separating the pair of lobes in each segment.

Vascular System. The dorsal blood vessel is unpaired throughout its length. There are four pairs of hearts, a pair in each of segments × to xiii, arising from the dorsal blood vessel.

Reproductive System. There are two pairs of testes, a pair in x and a pair in xi. Each testis is a small, compact, rounded structure attached by a slender stalk to the ventro-lateral aspect of the anterior septum of the segment. A pair of ovaries, similar in form and position to the testes, occurs in xiii. There are two pairs of spermathecae, a pair in viii and a pair in ix. Each spermatheca consists of an ovoidal sac with an anterior, rounded diverticulum not sharply differentiated from the sac. The whole organ is confined to one segment and opens by a

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Fig. 1—Octochactus tricystis. Ventral aspect, segments i–xx.
Fig. 2—O. tricystis. Dissection from the dorsal aspect.
Fig. 3—O. tricystis. Right anterior spermatheca; medial aspect.
c.g., cerebral ganglion: ch., chaeta; cl., clitellum; c.m., copulatory muscles; d.b.v., dorsal blood vessel; d.dlv., duct of the spermathecal diverticulum; div., spermathecal diverticulum; f.p., female pore; g., gizzard; h., heart; int., intestine; m., mouth; mn., micronephridial tubule; m.p., male pore; o., ovary; oe., oesophagus; oe.gl., oesophageal gland; o.f., ovarian funnel; p., prostate; pap., prostatic papilla; perl., peristomium; ph., pharynx; p.p., prostatic pore; pr., prostomium; pv., proventriculus; s., septum; sac, sac containing penial chaetae; sal. gl., salivary gland; s.i.v., supra-intestinal vessel; sp., spermathecal sac; sp.d., spermathecal duct; sp.p., spermathecal pore; t., testis; t.f., testicular funnel; t.pub., tuberculum pubertatis; v.d., vas deferens; v.s., vesicula seminalis.

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Fig. 1—O. sylvestris. Ventral aspect, segments i–xx.
Fig. 2—O. sylvestris. Dissection from the dorsal aspect.
Fig. 3—O. sylvestris. Left posterior spermatheca, medial aspect.

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Fig. 1—O. brucei. Ventral aspect, segments i–xxi.
Fig. 2—O. brucei. Dissection from the dorsal aspect.
Fig. 3—O. brucei. Right posterior spermatheca, lateral aspect.

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Fig. 1—Dinodrilus parvus. Ventral aspect, segments i–xxiii.
Fig. 2—D. parvus. Dissection from the dorsal aspect.
Fig. 3—D. parvus. Right anterior spermatheca, lateral aspect.

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Fig. 1—D. agilis. Ventral aspect, segments i–xx.
Fig. 2—D. agilis. Dissection from the dorsal aspect.
Fig. 3—D. agilis. Left posterior spermatheca, medial aspect.

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Fig. 1—D. montanus. Ventral aspect, segments i–xxi.
Fig. 2—D. montanus. Dissection from the dorsal aspect.
Fig. 3—D. montanus. Right posterior spermatheca, anterior aspect.

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Fig. 1—Hoplochaetina robusta. Ventral aspect, segments i–xxii.
Fig. 2—H. robusta. Dissection from the dorsal aspect.
Fig. 3—H. robusta. Right anterior spermatheca, lateral aspect.

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Fig. 1—H. pallida. Ventral aspect, segments i–xxi.
Fig. 2—H. pallida. Dissection from the dorsal aspect
Fig. 3—H. pallida. Right anterior spermatheca, posterior aspect.

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Fig. 1—H. Polycystis. Ventral aspect, segments i–xxi.
Fig. 2—H. Polycystis. Dissection from the dorsal aspect.
Fig. 3—H. Polycystis. Right anterior spermatheca, lateral aspect.

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Fig. 1—Leucodrilus digitocystis. Ventral aspect, segments i–xxiv.
Fig. 2—L. digitocystis. Dissection from the dorsal aspect.
Fig. 3—L. digitocystis. Right spermatheca, medial aspect.
Fig. 4—L. digitocystis. Penial chaeta.

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Fig. 1—L. fuscus. Ventral aspect, segments i–xix.
Fig. 2—L. fuscus. Dissection from the dorsal aspect.
Fig. 3—L. fuscus. Right spermatheca, anterior aspect.
Fig. 4—(a) L. fuscus. Penial chaeta. (b) L. fuscus. Normal segmental chaeta.

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short narrow duct to the exterior. (Plate 117, fig. 3.) Paired prostates are present in xvii and xix. The prostates are elongate, convoluted, tubular organs extending from a short muscular prostatic duct across the lateral and dorso-lateral aspects of the peritoneum almost to the dorsal mid-line. There are no penial chaetae nor copulatory muscles. The vesiculae seminales are paired, compact organs, a pair in each of xi and xii.

Micronephridia occur in every segment except the first. Those of ii form a fairly compact rounded cluster (similar to the mucus gland of O. multiporous) while those of all the segments posterior to ii are arranged in a narrow band on the lateral and dorso-lateral aspects of the peritoneum on each side of each segment.

Genus Dinodrilus

“Chaetae six pairs per segment. One oesophageal gizzard in one simple segment. Calciferous glands as mere dilatations of the oesophagus in the region of xiv–xvii (? always). Purely micronephridial. Sexual apparatus purely acanthodriline.” (Stephenson, 1930.)

The genus is confined to New Zealand and four species have been described by previous workers [including D. (Conicodrilus) kanieriensis]. These four species are:

  • D. benhami Beddard (1890)

  • D. suteri Benham (1905)

  • D. gracilis Ude (1905)

  • D. kanieriensis Benham (1945)

To these four species must now be added the three new species D. agilis, D. montanus and D. parvus, which are described in this paper.

The species of Dinodrilus may be identified from the following key:

a1 Eight chaetae on each segment anterior to clitellum, twelve on each of the remaining segments D. kanieriensis
a2 Twelve chaetae on each segment throughout
  b1 No calciferous glands
    c1 Gizzard in v D. parvus
    c2 Gizzard in vi D. montanus
    c3 Gizzard occupying vi and vii
      d1 Spermatheca with three ovoidal diverticula D. benhami
      d2 Spermatheca with six digitate diverticula D. gracilis
  b2 Two pairs of calciferous glands in xvi and xvii D. suteri
  b3 Five pairs of calciferous glands in ix, x, xi, xii and xiii D. agilis

D. agilis, by its possession of five pairs of calciferous glands, falls outside the definition of the genus. However, the definition may be extended to include such a variation.

The presence of only eight chaetae on each of the preclitellar segments of D. kanieriensis gives this species some claim to inclusion in the genus Octochaetus, but in all other respects the species closely resembles D. gracilis and has been included in the genus Dinodrilus.

The following are descriptions of the three new species, D. parvus, D. montanus, and D. agilis. Type specimens in the author's collection.

Dinodrilus parvus n.sp. (Plate 118, figs. 1–3)

Several specimens of this species were collected from the topsoil of Awapuka clay loam, under dense native bush, near the summit of

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the Mangamuku Range, south of Kaitaia. The specimen on which this description is based is 32·5 mm. long, 4 mm. in diameter, and has 113 segments.

The prostomium is tanylobous. The clitellum is darker in colour than the adjacent segments and surrounds xii to xvi. Chaetae commence on ii and there are twelve on each segment, arranged in pairs. On xxii their arrangement is as follows:

ab = cd = ef = 1 mm.; aa = 1·5 mm.; ff = 1·5 mm.; bc = de = 1·25 mm.

There are two pairs of spermathecal pores, a pair at 7/8 and a pair at 8/9. Each pore is in line with the chaetal interval ab on the same side. A single pair of female pores is present on xiv. The pore on each side is situated anterior to chaeta a. There are two pairs of prostatic pores, a pair on xvii and a pair on xix, situated on prominent rounded papillae. Each prostatic papilla lies in line with the chaetal intervals ab on the same side. The prostatic pores of each side are joined by a longitudinal groove which traverses xviii. A male pore is present in each groove on xviii between the chaetae a and b.

There are no nephridiopores. Dorsal pores commence at 12/13.

Internal Anatomy (Plate 119, fig. 2)

Septa viii/ix, ix/x, x/xi, xi/xii, xii/xiii and xiii/xiv are thickened and muscular.

Alimentary Canal. A small, globular, muscular pharynx, covered dorsally by salivary glands, occupies the first four segments. The gizzard has thick, strongly muscular walls and lies in v. The oesophagus extends from vi to xvii and lacks oesophageal glands. The intestine commences in xviii, is thin walled, and has a typhlosole.

Vascular System. The dorsal blood vessel is paired throughout its length and the two vessels do not fuse at the intersegmental septa. There are four pairs of dilated hearts, a pair each in x, xi, xii and xiii.

Reproductive System. There are two pairs of polylobate testes, a pair in × and a pair in xi, and a single pair of polylobate ovaries in xiii. There are two pairs of spermathecae, a pair in viii and a pair in ix. Each spermatheca is in the form of a small ovoidal sac opening by a duct to the exterior. A number of small diverticula form a semicircle around the anterior and lateral aspects of the duct. (Plate 118, fig. 3.) There are two pairs of simple tubular convoluted prostates, a pair in xvii and a pair in xix. There are no penial chaetae. A single pair of racemose vesiculae seminales is present in xi.

Micronephridia are present in each segment except the first.

Dinodrilus montanus n.sp. (Plate 119, figs. 1–3)

This species was discovered in Rimutaka sandy loam in a remnant of beech forest quarter of a mile north along the ridge of the Rimutaka Range from the highest point on the Wellington-Featherston road. Only two specimens were obtained. It is pink in colour, with a reddish streak running along the mid-dorsal line from the posterior border of the clitellum to the anus. The clitellum is darker in colour than the remainder of the body and completely surrounds segments xiii–xvi.

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The specimen described is 55 mm. in length and 4 mm. in diameter and has 109 segments. The prostomium is epilobous. There are 12 chaetae on each segment, almost evenly spaced around the circumference of the segments. On xxiv the arrangement of the chaetae is as follows:

ab = 1 mm.; cd = 1 mm.; ef = 1 mm.; aa = 1·25 mm.; bc = 1 mm.; de = 1 mm.; ff = 1·75 mm.

No spermathecal pores are visible externally. There is a pair of female pores on xiv, a pore anterior and slightly medial to chaeta a on each side. The two pairs of prostatic pores occupy the apices of prominent rounded papillae, a pair on xvii and a pair on xix, in line with the chaeta b. Chaeta b is absent on these two segments. A groove with tumid borders joins the two prostatic pores of each side of the body, passing across xviii in an arc lateral to chaeta b. The male pores lie, one on each side, in these grooves beside chaeta b of xviii.

An unpaired tuberculum pubertatis forms a white projecting band across the ventral surface of x, extending from chaeta a of one side to chaeta a of the other side.

No nephridiopores are visible. Dorsal pores commence at 16/17 and occur in each intersegmental groove posterior to 16/17.

Internal Anatomy (Plate 119, fig. 2)

There are no specially thickened septa.

Alimentary Canal. A strongly muscular pharynx occupies the first four segments. A thin-walled proventriculus in v joins the pharynx to the long thick-walled muscular gizzard in vi. The oesophagus extends from vii to xvii and opens into the wide thin-walled intestine in xviii. There are no oesophageal glands. The intestine lacks a typhlosole.

Vascular System. The dorsal blood vessel is paired throughout its length. A slender supra-intestinal vessel runs along the mid-dorsal line of the oesophagus from × to xiii and the four pairs of hearts arise from that vessel, a pair in each of the segments × to xiii.

Reproductive System. Two pairs of testicular funnels are present, a pair in each of × and xi, but the testes were not visible in the specimen examined. The ovaries are easily identifiable in xiii and consist of a group of moniliform threads attached to the anterior septum of the segment, ventro-laterally on each side. There are two pairs of spermathecae, a pair in viii and a pair in ix. Each spermatheca consists of an antero-posteriorly flattened conical sac opening by a narrow duct to the exterior, close to the anterior septum of the spermathecal segment. Five small digitate diverticula are grouped around the base of the sac and open into the duct. (Plate 119, fig. 3.) Two pairs of prostates are present, a pair in xvii and a pair in xix. They are extremely convoluted, slender, tubular organs and are confined to a single segment in each case. There are neither penial chaetae nor copulatory muscles associated with the prostates. The vesiculae seminales are paired racemose organs lying lateral to the oesophagus in xi and xii.

Micronephridia occur in the form of a band of long slender tubules on the ventro-lateral and lateral aspects of each side of every segment except i.

– 566 –

Dinodrilus agilis n.sp. (Plate 120, figs. 1–3)

I have only one specimen of this species, collected from the northwest corner of the Kaingaroa State Forest (under Pinus strobus) about five miles east of Waiotapu. It is reddish-brown dorsally and pale ventrally with a very prominent sienna brown clitellum completely surrounding segments xiii–xvi. It is 105 mm. in length, 4 mm. in diameter and has 154 segments.

The prostomium is epilobous. There are twelve chaetae on each segment, arranged in pairs, equidistantly spaced around each segment. On xxiv:

ab = cd = ef = 1 mm.; aa = bc = de = dd = 1·25 mm.

There are two pairs of spermathecal pores at 7/8 and 8/9, in line with chaeta b. The female pores occur on xiv, slightly anterior and medial to the chaeta a. There are two pairs of prostatic pores on xvii and xix, each pore situated on the apex of a prominent dome-like tumid papilla in line with the chaeta b. A tumid longitudinal ridge joins the two prostatic pores on each side, passing between the chaetae a and b on xviii and a groove passes along the axis of this ridge. The single pair of male pores lie in these grooves, one on each side on xviii, between the chaetae a and b.

Dorsal pores commence at 16/17 and occur in every intersegmental groove posterior to 16/17.

Internal Anatomy (Plate 120, fig. 2)

Alimentary Canal. The pharynx occupies the first four segments. It is small and rounded, has few extrinsic muscles and has two large dorso-lateral clusters of salivary glands. There is a short, wide, thin-walled proventriculus in v and a long muscular gizzard in vi. The oesophagus extends from vii to xvi and has five pairs of small, rounded, calciferous glands in ix, x, xi, xii and xiii. The intestine commences in xvii. It is wide and thin walled and has a typhlosole.

Vascular System. The dorsal blood vessel is paired throughout its length. There are four pairs of dilated hearts in segments x, xi, xii and xiii rising from the dorsal blood vessel.

Reproductive System. There are two pairs of small lobate testes and their funnels in × and xi and a single pair of small lobate ovaries with their funnels in xiii. Two pairs of spermathecae occur in viii and ix. Each consists of a small cylindrical sac with four curved finger-like diverticula opening into its duct close to the body-wall. (Plate 120, fig. 3.) There are two pairs of convoluted tubular prostates in xvii and xix, each opening by a narrow muscular duct to the exterior. There are no penial chaetae, but several strong copulatory muscles arise from the dorso-lateral aspects of the peritoneum and are inserted on the peritoneum close to the terminations of the prostatic ducts. There are two pairs of small vesiculae seminales in xi and xii.

Large numbers of very small micronephridial tubules form a compact mat on the lateral aspects of the peritoneum in every segment except the first.

Genus Hoplochaetina Michaelsen

“Setal arrangement perichaetine. One oesophageal gizzard in one simple segment. Calciferous glands as mere dilations of the oesophagus

– 567 –

in xv and xvi. Purely micronephridial (?). Sexual apparatus purely acanthodriline.” (Stephenson, 1930.)

The genus is confined to New Zealand.

Two species were described by Benham (1902) and referred by him to the genus Plagiochaeta Benham (1892). These two species were subsequently removed from the genus Plagiochaeta to a new genus Hoplochaetina by Michaelsen, since Plagiochaeta is characteristically meganephric, whereas these two species are micronephric. There has been no further record of the genus, and the three species described in this paper bring the total known number of species to five.

The five species may be recognised from the following key:

a1 One pair of vesiculae seminales H. robusta n.sp.
a2 Two pairs of vesiculae seminales
b1 Spermatheca with one diverticulum H. pallida n.sp.
b2 Spermatheca with small diverticula arranged in a semicircle H. polyoystis n.sp.
a3 Three pairs of vesiculae seminales
c1 Ovaries and testes attached to the anterior septa of their respective segments H. rossii (Benh.)
c2 Ovaries and testes attached to the ventral aspect of the peritoneum in their respective segments H. ricardi (Benh.)

The following are descriptions of the three new species H. robusta, H. pallida and H. polycystis. Type specimens in author's collection.

Hoplochaetina robusta n.sp. (Plate 121, figs. 1–3)

A single specimen of this large pink earthworm was collected together with a large number of specimens of the introduced species Allolobophora caliginosa from Waiotira clay loam, under a remnant of native forest among pasture lands two miles south-east along the Mangakahia Valley road from Pakotai, near Whangarei. It is 98 mm. in length, has 166 segments, and a diameter of 7·5 mm. for most of its length.

There is no marked clitellum. The prostomium is epilobous. The chaetae, which commence on ii, are perichaetine in arrangement, and about 48 on each segment, closely spaced around the circumference of the segments, except for a gap of 1·75 mm. between corresponding chaetae a of each segment.

There are two pairs of spermathecal pores, a pair at 7/8 and a pair at 8/9. The pores on each side are in line with the chaeta fourth from the ventral mid-line. A single pair of female pores is present on xiv, each pore situated slightly anterior to the corresponding most medial of the ventral chaetae of that segment. There are two pairs of prostatic pores, a pair on xvii and a pair on xix, each pore situated on a raised white papilla. A longitudinal groove joins the two prostatic pores of each side, traversing xviii, and a male pore lies in each of these grooves, on xviii.

Nephridiopores are not visible. Dorsal pores commence at 19/20, and are present in each intersegmental groove posterior to this.

Internal Anatomy (Plate 121, fig. 2)

Septa vi/vii, vii/viii, viii/ix, ix/x, x/xi, xi/xii and xii/xiii are muscular and thickened.

– 568 –

Alimentary Canal. A strong muscular pharynx occupies the first four segments. An elongate, muscular-walled gizzard lies in v. The oesophagus extends from vi to xvii, and has two pairs of calciferous glands, a pair in xiv and a pair in xv. The intestine commences in xviii and has a typhlosole.

Vascular System. The dorsal blood vessel is paired posterior to v/vi, and the two vessels fuse at each septum. There are four pairs of dilated hearts, a pair each in segments × to xiii.

Reproductive System. There are two pairs of free lobate testes, a pair in × and a pair in xi, and a pair of lobate ovaries in xiii. Two pairs of spermathecae are present, a pair in viii and a pair in ix, each in the form of a rounded sac, with a complete ring of small rounded diverticula encircling its duct. (Plate 121, fig. 3.) Two pairs of extremely convoluted prostates are present, a pair in xvii and a pair in xix. Each prostate opens to the exterior by a narrow duct in its encircling segment. There is a single pair of racemose-vesiculae seminales in xi.

Very small micronephridial tubules are present in each segment except the first.

Hoplochaetina pallida n.sp. (Plate 122, figs. 1–3)

This is a large pink earthworm, common in the subsoil of uncultivated areas in the vicinity of Whangarei, and it resembles in gross form Octochaetus multiporus Beddard (1892). The specimen described was collected from Omu clay loam, at a depth of twelve inches, in a remnant of native forest beside the Whangarei-Dargaville road, one mile and a half west of Tangowahine. It is 200 mm. in length, has 157 segments, and a diameter of about 10 mm. When killed in alcohol it ejects a dirty white coelomic fluid, and the body becomes flaccid and difficult to handle.

The prostomium in tanylobous. The clitellum is buff in colour, completely surrounding xiv to xvi, and covering the dorsal and lateral surfaces of xvii. Chaetae are perichaetine in arrangement, and very numerous. They are more or less evenly spaced around the circumference of the segments except for a wide ventro-medial gap.

There are two pairs of spermathecal pores, at 7/8 and 8/9, situated ventro-laterally, 3 mm. from the ventral midline on each side. There is a single pair of female pores on the anterior aspect of xiv, adjacent to the ventral midline. They are so close together that they appear to the naked eye as a single pore. Two pairs of prostatic pores occur on prominent papillae, a pair on xvii and a pair on xix. The pores are situated 3·5 mm. from the ventral midline. A longitudinal groove joins the two prostatic pores on each side, and a male pore lies in each of these grooves, on xviii.

Nephridiopores are not visible.

Internal Anatomy (Plate 122, fig. 2)

Septa viii/ix, ix/x, x/xi, xi/xii, xii/xiii and xiii/xiv are thickened and muscular.

Alimentary Canal. The pharynx is rounded and muscular, and occupies the first four segments. A strongly muscular gizzard lies in v.

– 569 –

The oesophagus extends from vi to xvi, and has two pairs of calciferous glands, a pair in xiv and a pair in xv. The intestine commences in xvii, is very thin walled, and has a marked typhlosole.

Vascular System. The dorsal blood vessel is paired, except in the first five segments, and the two vessels remain separate as they pass through the septa. There are four pairs of dilated hearts, a pair each in x, xi, xii and xiii.

Reproductive System. Two pairs of lobate testes are present, a pair in × and a pair in xi, and there is a single pair of lobate ovaries in xiii. There are two pairs of spermathecae, a pair in viii and a pair in ix. Each spermatheca is in the form of a spheroidal sac opening by a narrow duct to the exterior. Surrounding the duct is a curved diverticulum, with its surface upraised into rounded pustules, which opens laterally into the duct of the spermatheca. (Plate 122, fig. 3.) There are two pairs of elongate, coiled, tubular prostates, a pair each in xvii and in xix. Each prostate is wholly confined to one segment. Large copulatory muscles are present in the region of the prostates (as in H. rossii Benham, 1902). There are two pairs of racemose vesiculae seminales, a pair in ix and a pair in xi.

Micronephridia commence in ii, and a pair of small ventro-lateral clusters of micronephridial tubules is present in each segment posterior to this.

Hoplochaetina polycystis n.sp. (Plate 123, figs. 1–3)

A single specimen of this very large pink earthworm was collected from a depth of about twelve inches in Awapuka clay loam, under dense native bush, near the summit of the Mangamuku Range to the south of Kaitaia. It is 219 mm. in length, has 168 segments, and is 8 mm. in diameter. The prostomium is epilobous. The chaetae are perichaetine in arrangement, closely spaced around the segments except for a ventro-medial gap, and number about 70 on each segment. The clitellum is darker in colour than the rest of the body and surrounds segments xiv to xix.

Spermathecal pores are not visible externally. There is a single pair of female pores on xiv. Each pore lies anterior to the chaeta third from the ventral mid-line on the corresponding side. There are two pairs of prostatic pores, a pair on xvii and a pair on xix, each pore opening on a dome-like papilla situated 3 mm. from the ventral midline. A longitudinal groove joins the two prostatic pores of each side and a male pore lies in each of these grooves on xviii.

There are no nephridiopores. Dorsal pores commence at 11/12 and are present in each intersegmental groove posterior to this.

Internal Anatomy (Plate 123, fig. 2)

Septa vi/vii, vii/viii, viii/ix, ix/x, x/xi, xi/xii, xii/xiii and xiii/xiv are very muscular and greatly thickened. There are no septa anterior to iv/v.

Alimentary Canal. The pharynx is rounded and muscular and occupies segments i–iv. A short gizzard with thick muscular walls lies in v. A dilated oesophagus extends from vi to xix. There are no oesophageal glands. The intestine commences in xx and has a typhlosole.

– 570 –

Vascular System. The dorsal blood vessel is paired throughout its length. There are five pairs of hearts surrounding the oesophagus, one in each of ix, x, xi, xii and xiii, those in ix being much more slender than those in × to xiii.

Reproductive System. There are two pairs of lobate testes close to the ventral midline, a pair in × and a pair in xi, and a single pair of lobate ovaries close to the ventral midline in xiii. There are two pairs of spermathecae, a pair in viii and a pair in ix. Each is in the form of a small sac. flattened dorso-ventrally and opening by a short duct to the exterior. A cluster of small diverticula open into the spermathecal duct. (Plate 123, fig. 3.) Two pairs of convoluted tubular prostates are present, a pair in xvii and a pair in xix. There are no penial chaetae, but strong copulatory muscles extend from the region of the prostatic ducts to the lateral aspects of the body-wall in xvii, xviii and xix. There are two pairs of racemose vesiculae seminales, a pair in ix and a pair in xii.

Micronephridia commence in v. There is a small cluster of micronephridial tubules close to the ventral nerve cord on each side of each of the segments.

Genus Leucodrilus n.g.

Genotype: Leucodrilus digitocystis n.sp.

Chaetae eight on each segment, arranged in pairs. One oesophageal gizzard in one simple segment. Purely micronephridial. Sexual apparatus microscolecine.

Two species of this new genus are described below. They were both collected from Hawke's Bay, on the east coast of the North Island of New Zealand.

The two species may be readily recognised, since the spermathecal pores of one (L. digitocystis) are in 8/9 while those of the other (L. fuscus) are in 7/8 and have prominent tumid lips.

The following are descriptions of the two new species. Type specimens in the author's collection.

Leucodrilus digitocystis n.sp. (Plate 124, figs. 1–4)

Eight specimens of this large pink earthworm were collected from Maraetotara sandy loam under a small remnant of native rain forest beside the Waimarama-Okaihau road, Hawke's Bay. Of the eight specimens, only one possesses a clitellum and is obviously sexually mature. It is noteworthy that this specimen is much smaller (97 mm. in length, 6 mm. in diameter, with 157 segments) than some of the other specimens which are apparently not sexually mature (up to 180 mm. in length, 12 mm. in diameter, with over 200 segments).

This description is based on the mature specimen mentioned above. It is very lightly pigmented dorsally and unpigmented ventrally, with a prominent pink clitellum surrounding segments xiv–xvii and extending over part of the dorsal surface of xiii.

The prostomium is epilobous. There are eight chaetae on each segment, arranged in pairs. On segment xxiv:

ab = cd = 1·25 mm.; aa = 2·5 mm.; bc = 2·5 mm.; dd = 6 mm.

– 571 –

The first five segments have no secondary annulations. Segment vi is biannulate and all the segments posterior to vi are triannulate.

There is a single pair of spermathecal pores at 8/9 in line with the chaeta b and each pore is bounded anteriorly by a small tuberculum pubertatis. Further paired tubercula pubertatis occur on ix and x, in line with the chaetae ab, and on xix, xx, xxi, xxii and xxiii in line with the chaetae ab. There is a single pair of female pores on xiv, a pore slightly anterior to the chaeta a on each side. A single pair of prostatic pores occurs on xvii, each pore situated on the apex of a prominent white papilla in line with the chaetae ab. There is a pair of male pores on the anterior margin of xviii in line with the prostatic pores.

There are no nephridiopores visible externally. Dorsal pores commence at 17/18 and occur in every intersegmental groove posterior to this.

In its external features the species very closely resembles some of the species of Octochaetus, but the possession of only one pair of prostatic pores on xvii instead of two pairs on xvii and xix makes it necessary to place the species in the genus Leucodrilus.

Internal Anatomy (Plate 124, fig. 2)

The septa vii/viii, viii/ix, ix/x, x/xi, xi/xii, xii/xiii and xiii/xiv are muscular and thickened.

Alimentary Canal. The pharynx is rounded and muscular and occupies the first four segments. A wide, thin-walled proventriculus joins the pharynx to the thick-walled muscular gizzard which lies in vi. The oesophagus extends from vii to xvi and there are no oesophageal glands. The intestine commences in xvii. It is thin walled and wide and has a marked typhlosole.

Vascular System. The dorsal blood vessel is unpaired throughout its length. There are four pairs of hearts in the segments x to xiii, those of xiii being greatly dilated.

Reproductive System. There are two pairs of testes, a pair in x and a pair in xi, and a single pair of ovaries in xiii. There is a single pair of spermathecae in ix. Each spermatheca consists of a large, thin-walled ovoidal sac opening by a wide muscular duct to the exterior. A recurved digitate diverticulum opens by a short duct into the anterior aspect of the spermathecal duct (Plate 124, fig. 3.) There is only one pair of prostates. Each is a tubular organ of great length, opening to the exterior by a short muscular duct in xvii. The two prostates are of unequal extent, the left prostate extending from xvii straight back through the intersegmental septa into xxiii, where it terminates in a distal coiled portion, while the right prostate extends from xvii back only as far as xxi, where it terminates in a distal coiled portion. An elongate sac containing penial chaetae lies on the lateral aspect of the prostates and extends from xvii to xxi. The penial chaetae have an elongate shaft, slightly irregular in shape, and are sharply curved at the tip. (Plate 124, fig. 4.) There are two pairs of vesiculae seminales, in xi and xii. They consist of botryoidal masses of vesicular tissue completely surrounding the oesophagus in xi and xii.

– 572 –

Micronephridia commence in ii and occur in every segment posterior to this in the form of a small cluster of tubules on each side of the nerve cord.

Leucodrilus fuscus n.sp. (Plate 125, figs. 1–4)

Four specimens of this very large earthworm were collected on a steep bush-clad hillside (ngaio, titoki) beside the Gisborne-Tiniroto-Wairoa road about twenty miles north of Wairoa.

The specimen on which this description is based is 296 mm. in length and 10·5 mm. in diameter, with 264 segments. It is sienna-brown dorsally and pale silvery-white ventrally, with a prominent brown clitellum covering the dorsal and lateral aspects of segments xiii–xvii. Segments ii–v are biannulate and from vi onwards the segments are triannulate.

The prostomium is epilobous. There are eight chaetae on each segment, arranged in pairs. On xxiv:

ab = cd = 1·5 mm.; aa = 4·5 mm.; bc = 2·5 mm.; dd = 4 mm.

There is a pair of spermathecal pores at 7/8, in line with chaeta a. The spermathecal pores are bounded by very prominent transverse lips. The female pores are a pair of small, transverse, slit-like openings slightly anterior to chaeta a, one on each side of xiv. The prostatic pores occupy the apices of a pair of prominent conical papillae in line with the chaetae ab. Prominent penial chaetae project from a pore close to each prostatic pore. Male pores are not visible externally. There are no tubercula pubertatis. I can find no dorsal pores anterior to 7/8, but there is one at 7/8 and in every intersegmental groove posterior to this point.

Internal Anatomy (Plate 125, fig. 2)

The septa vii/viii, viii/ix, ix/x, x/xi, xi/xii and xii/xiii are muscular and thickened.

Alimentary Canal. The pharynx occupies segments i–iv. It is covered dorsally and laterally by salivary glands and its extrinsic muscles are all inserted on to its posterior margin. There is a short, thin-walled proventriculus in v, followed by an elongate, thick-walled, muscular gizzard in vi. The oesophagus extends from vii to xvi and bears a single pair of prominent rounded calciferous glands in xii. The intestine commences in xvii, is very thin-walled and has a marked typhlosole.

Vascular System. The dorsal blood vessel is unpaired throughout its length. Four pairs of dilated moniliform hearts arise from the dorsal vessel in segments x–xiii.

Reproductive System. There are two pairs of very minute testes and their funnels in × and xi. The two vasa deferentia of each side lie side by side on the ventral aspect of the peritoneum and run back to segment xvii, where they fuse. The combined duct then passes across the lateral aspect of the prostatic duct, through septum xvii/xviii and opens to the exterior in xviii just behind that septum. The ovaries are also small paired organs, in xiii, with a short duct leading from the funnel to open to the exterior in xiv. There is a single pair of spermathecae in viii. Each consists of a large, flattened, oval sac with a small, lateral, rosette shaped diverticulum opening by a narrow duct

– 573 –

into the anterior aspect of the main spermathecal duct, close to the body-wall. (Plate 125, fig. 3.) A pair of elongate, convoluted, tubular prostates arise from the strongly muscular prostatic ducts in xvii. The prostates pass back along the lateral aspects of the body-wall from xvii, terminating in xxi. The penial chaetae lie in a short sac, medial to each prostatic duct, in xvii. Each penial chaeta has a stout, slightly curved shaft with a sharply recurved, pointed tip. (Plate 125, fig. 4a.) The segmental chaetae are sigmoid. (Plate 125, fig. 4b.) There are two pairs of finely racemose vesiculae seminales in xi and xii, surrounding the lateral aspects of the oesophagus.

Micronephridia commence in ii. They take the form of a small, compact cluster of tubules on each side of the ventral nerve cord in each segment.

Remarks. L. digitocystis and L. fuscus are similar in many respects, but they may be distinguished by the following points of difference:

  • (i) L. digitocystis is pink in colour; L. fuscus is sienna-brown.

  • (ii) The spermathecal pores of L. digitocystis are in the intersegmental groove 8/9 and have no prominent lips; those of L. fuscus are in the groove 7/8 and have prominent tumid lips.

  • (iii) The spermathecal diverticulum of L. digitocystis is digitate; that of L. fuscus is rosette shaped.

  • (iv) The penial chaetae of L. digitocystis are slender and gently curved at the tip; those of L. fuscus are stout and sharply recurved at the tip, the point actually being reversed in direction.

References

Beddard, F. E., 1890. Further Notes on New Zealand Earthworms, with Observations on the Known Aquatic Species. Quart. Jour. Micr. Sci., vol. 30.

—— 1892. Further Notes on New Zealand Earthworms. Proc. Zool. Soc., London, 1892, p. 668.

Benham, W. B., 1892. Quart. Jour. Micr. Sci., vol. 32, p. 289.

—— 1898. A Re-examination of Hutton's Types of New Zealand Earthworms. Trans. N.Z. Inst., vol. 31, p. 156.

—— 1902. On the Old and some New Species of Earthworms belonging to the Genus Plagiochaeta. Trans. N.Z. Inst., vol. 35, p. 277.

—— 1904. On Some Edible and Other New Species of Earthworms from the North Island of New Zealand. Proc. Zool. Soc., London, 1904 (2), p. 220.

—— 1905. Additional Notes on the Earthworms of the North Island of New Zealand. Trans. N.Z. Inst., vol. 38, p. 239.

—— 1945. An Earthworm with Four Penes, Conicodrilus, genus novum. Trans. Roy. Soc. N.Z., vol. 75, p. 23.

—— 1950. On Cryptochaeta, a New Genus of Earthworms; and a Nomenclatural Muddle Solved. Trans. Roy. Soc. N.Z., vol. 78, p. 324.

Hutton, F. W., 1876. On New Zealand Earthworms in the Otago Museum. Trans. N.Z. Inst., vol. 9, p. 350.

Michaelsen, W., 1921. Oligochaten von Westlichen Vorderindien und ihre Beziehungen zur Oligochaeten-fauna von Madagascar und den Seychellen. Mitt. Zool. Mus. Hamburg, vol. 38, p. 37.

Stephenson, J., 1915. On some Indian Oligochaeta, mainly from Southern India and Ceylon. Mem. Ind. Mus., vol. 6, p. 103.

—— 1923. Oligochaeta, in the Fauna of British India Series. London, 1923.

—— 1930. The Oligochaeta. Clarendon Press, Oxford, 1930.

Ude, H., 1905. Terricole Oligochaeten von den Inseln der Sudsee. Zeitt. fur Wiss. Zool., vol. 83.