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Volume 80, 1952
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Internal Anatomy (Plate 13, fig. 2)

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

Alimentary Canal. The pharynx occupies the first four segments and posteriorly it is covered dorsally and laterally by salivary glands. The gizzard has thick muscular walls and lies in v. The oesophagus extends from vi to xv and there are no oesophageal glands. The intestine commences in xvi.

Vascular System. The dorsal blood vessel is unpaired. There are four pairs of hearts, a pair in each of ix, x, xi and xii. Those of ix are much more slender than those of the subsequent segments.

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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. The testes and ovaries have a similar, compact, lobate form and are situated one on each side of the ventral midline, attached to the anterior septa of their respective segments. There are two pairs of spermathecae, a pair in viii and a pair in ix. Each consists of a large sac, almost spheroidal, but with a finger-like lobe lying over its upper surface and projecting towards the midline. The sac opens to the exterior by a long, thickwalled duct, and an elongate pyriform diverticulum opens medially into the duct (Plate 13, fig. 3). In one specimen the right anterior spermatheca was situated in vii instead of viii, but its duct passed back through vii and opened to the exterior at the intersegmental furrow 7/8, as is normal in the species. The prostates are short, curved, tubular organs, lying one on each side of the ventral nerve cord. They open to the exterior through a narrow duct, one on each side of xviii, and the organs extend back from xviii to xix. There are three pairs of racemose vesiculae seminales, a pair in each of ix, xi and xii. Those of ix are small rounded organs, attached to the posterior septum of the segment, while those of xi and xii are larger organs, extending around the lateral aspects of the oesophagus and attached to the anterior septa of their respective segments.

Micronephridia occur in every segment except the first, as a mat of small, slender tubules, covering the lateral aspects of the peritoneum. In the eleven most posterior segments there are very small paired meganephridia, in addition to the micronephridia. The meganephridia do not appear to be functional. Each consists merely of a tightly coiled tubule with no obvious funnel or elimination duct, lying close to the ventral nerve cord on its side of the segment.

Megascolides fuscus n.sp. (Plate 14, figs. 1–3)

Several specimens of this large brown earthworm were collected from topsoil

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Fig. 1—Megascolides viridis. Ventral aspect, segments i–xxi.
Fig. 2—M. viridis. Dissection from the dorsal aspect.
Fig. 3—M. viridis. Left anterior spermatheca anterior aspect.

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Fig. 1—Megascolides ruber. Ventral aspect segments i–xxi.
Fig. 2—M. ruber. Dissection from the dorsal aspect.
Fig. 3—M. ruber. Left posterior Spermatheca, lateral aspect.

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Fig. 1—Megascolides parvus. Ventral aspect, segment i–xx.
Fig. 2—M. parvus. Dissection from the dorsal aspect.
Fig. 3—M. parvus. Right spermatheca of viii, posterior aspect.

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Fig. 1—Megascolides raglani. Ventral aspect, segments i–xxiii.
Fig. 2—M. raglani. Dissection from the dorsal aspect.
Fig. 3—M. raglani. Right posteior spermatheca. posterior aspect.

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Fig. 1—Megascolides fuscus. Vential aspect, segments i–xx.
Fig. 2—M. fuscus. Dissection from the dorsal aspect.
Fig. 3—M. fuscus. Left spermatheca, medial aspect.

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Fig. 1—Megascolides irregularis. Ventral aspect, segments i–xx.
Fig. 2—M. irregularis. Dissection from the dorsal aspect.
Fig. 3—M. irregularis. Left posterior spermatheca, anterior aspect.

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Fig. 1—Megascolides alba. Ventral aspect, segments i–xxxi.
Fig. 2—M. alba. Dissection from the dorsal aspect.
Fig. 3—M. alba. Left posterior spermatheca, posterior aspect.

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Fig. 1—Megascolex novae-zealandiae. Ventral aspect, segments i–xx.
Fig. 2—M. novae-zealandiae. Dissection from the dorsal aspect.
Fig. 3—M. novae-zealandiae. Right anterior spermatheca, lateral aspect.

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Fig. 1—Pheretima campestris. Ventral aspect, segments i–xix.
Fig. 2—P. campestris. Dissection from the dorsal aspect.
Fig. 3—P. campestris, Left posterior spermatheca anterior aspect.

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

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Fig. 1—Perionyx egmonti. Ventral aspect, segments i–xx.
Fig. 2—P. egmonti. Dissection from the dorsal aspect.
Fig. 3—P. egmonti. Right posterior spermatheca, medial aspect.
Fig. 4—P. egmonti. Right prostate, ventro-lateral aspect.
Fig. 5—P. egmonti Vertical section through prostate. (Diagrammatic).

acc gl., accessory gland, e.g., cerebral ganglion, ch., chaeta, el, clitellum; c.p.e., central prostatic cavity; d.b.v., doisal blood vessel, d.div., duct of spermathecal diverticulum, div., spermathecal diverticulum, f.p., female pore; g., gizzard, h., heart, int., intestine; l., lobule of piostate; m., mouth; m.f., “male field”, m g., mucus gland, mn., meronephridial tubule, m p., male pore, n, meganephridial tubule; o., ovary, oe., oesophagus; oe.gl., oesophageal gland, o f., ovarian funnel; p., prostate; pap., prostatic papilla, p.d, prostatic duct, peri. peristomium, ph, pharynx, pr, prostomium, pv., proventriculus; s, septum; sal.gl., salivary gland, sh., sheath; s.i.v., supra-intestinal vessel; sp., spermatheca; sp.d., spermathecal duct, sp.p, spermathecal pore; t., testis, t.f., testicular funnel; t.pub., tuberculum pubertatis, v.b.v., ventral blood vessel, v.n.c., ventral nerve cord, v.s., vesicula seminalis.

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and subsoil in Taupo sandy silt in areas of native rain forest and exotic forest (Pinus spp.) in the Rotorua district.

The specimen on which this description is based is 251 mm. in length and 10 mm. in diameter and has 268 segments. The clitellum is greyish-brown and is developed over the entire surface of xv and xvi and on the dorsal and lateral surfaces of xiv, xvii and xviii. The prostomium is epilobous. The first six segments are biannulate, segments vii–xviii are quadriannulate and the post-clitellar segments are biannulate. There are eight chaetae on each segment, arranged in pairs. On xxiv: ab = 1·25 mm.; cd = 2·25 mm.; aa = 4·4 mm.; bc = 4·5 mm.; dd = 10 mm.

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There is only one pair of spermathecal pores, at 7/8 in line with the chaeta b. There is a single pair of female pores slightly anterior and lateral to the chaeta a on xiv. The male pores open on the apices of a single pair of prominent rounded papillae on xviii. The chaeta a is absent on xviii and in its place on each side is the papilla bearing the male pore. There are no tubercula pubertatis. Dorsal pores occur in every intersegmental groove posterior to the clitellum. There are no nephridiopores.

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