The Classification and Reproductive Organs of New Zealand Land Planarians,
Part I.—Geoplana Graffii Dendy and Arti-Oposthia Howesi (Dendy).
[Read before Otago Branch, May 9, 1944; received by the Editor, May 15, 1944; issued separately, December, 1944.]
The material on which this paper is based includes: (1) Material collected in New Zealand and presented to the Zoology Department, and (2) selected specimens from Dendy's type material deposited by him in the British Museum. Sir William Benham examined and made general notes on all Dendy's material in 1937, and he has kindly made these notes available to the writer. The British Museum specimens examined by the writer were selected from the collection on the basis of Benham's notes.
The nomenclature of the New Zealand land planarians is somewhat complicated by the fact that Dendy did not designate holo-types for most of his species, therefore there are a number of syntypes and the position is further complicated by the subsequently proved identity of several of Dendy's species and varieties, and by the fact that in other cases more than one species is included among the syntypes of a single species of Dendy.
Geoplana graffii Dendy.
1895. Geoplana agrioola Dendy, Trans. N.Z. Inst., vol. xxvii, pp. 184–185.
1895. Geoplana inequalistriata Dendy, Trans. N.Z. Inst., vol. xxvii, pp. 182–183.
1890. Geoplana, iris Dendy (in part), Trans. N.Z. Inst., vol. xxviii, p. 213.
1897. Geoplana graffii var. occidentalis Dendy, Trans. N.Z. Inst., vol. xxix, pp. 200–201.
1901. Geoplana graffii var. nodusa, Deudy. Trans. N.Z. Inst., vol, xxxiii, pp. 227–228.
1901. Geoplana graffii var. wharekauriensis Deudy, Trans. N.Z. Inst., vol. xxxiii, pp. 226–227.
Locality. G. graffii lives under stones and wood in damp situations and is one of the commonest land planarians found in the Dunedin district. It is probably equally common elsewhere judging by the number of varieties found by Dendy (1900) in various parts of Otago, Canterbury and the Chatham Islands.
External Characters. The worm is fairly large, broad, and tough, and is one of the few land planarians which can be kept alive under laboratory conditions for a long period. The average length of a living specimen is about 45 mm. The dorsal surface is greeny-brown speckled with long slits of a bluish-white colour, which often gives the appearance of iridescence. There is a broad median stripe varying in colour from yellow to tan, with a dark line on each edge. Marginal bands are paler than the ground colour and are speckled. The ventral surface is paler than the dorsal, with dark brown speckles and a pale median stripe.
The mouth is approximately half way along the ventral surface, and the genital pore is nearer the mouth than the posterior end.
Eyes are very numerous along both sides and round the anterior end.
This planarian is easily recognised by its broad shape, median stripe, and the characteristic bluish-white slits on the dorsal surface, which tends to look iridescent.
Reproductive Organs. The genital atrium is small, and is separated by a muscular partition into male (m.at.) and female (f.at.) parts. The amount of separation varies, presumably according to the amount of contraction of the animal on fixing. Into the male atrium open the male duct and an accessory gland and into the female open the oviduct (od.) and an accessory gland.
Paired ovaries lie in the usual ventral anterior position. The two oviducts join together behind the atrium and enter a wider glandular canal (g.c.), which receives numerous shell glands (sh.g.) and opens into the female atrium.
The numerous testes are arranged in two lateral bands between the oviducts and the lateral margins. They extend from the region of the ovaries to the atrium. The vasa efferentia arise from the ventral surfaces of the testes and enter a longitudinal vas deferens (v.d.) one on each side extending from the pharynx to the penis bulb (b.p.). Here the two ducts turn dorsally and join to form a short, narrow, glandular seminal duct (d.s.) which enters the massive cylindrical penis bulb enclosing the wide seminal vesicle (v.s.) with its narrow opening into the male atrium. There is no penis papilla.
The two accessory glands are a constant feature of G. graffii, having been found in all fully-grown specimens examined at various times of the year, and so far as can be judged, are not seasonal. I have examined specimens collected at fortnightly intervals for four months of the year, and in all of these the accessory glands were always well-developed in fully-grown worms. The structure of both accessory glands is essentially the same. Each lies in its own muscle mass, which can easily be separated from the surrounding parenchyma. The gland consists of a wide reservoir (re.) which in mature worms contains lumps of secretion. This is followed by a narrow coiled duct (d.c.) with valves (v) at intervals along its length. The coiled duct is surrounded by a wide sheath of circular muscles and enters a large, muscular vesicle (v.m.), which opens into the genital
atrium through a narrow duct of varying length. The coiled duct and the muscular vesicle are both lined with ciliated epithelium. The accessory gland has no connection with the gut, as is often the case with the bursa copulatrix.
The function of the accessory glands is obscure. They somewhat resemble the bursa copulatrix of land planarians which is a receptacle for sperms received during copulation, the sperms remaining there only for a short time before passing up the oviducts to fertilize the ripe eggs. Von Graff (1899, p. 178) describes for the genus Arti-oposthia receptacula seminis which in their structure resemble very closely the accessory glands of G. graffii. That of A. fletcheri is especially similar, with its muscular ring (cl.) where the narrow, muscular, coiled duct enters the wide terminal vesicle. Actually the accessory glands of G. graffii most closely resemble adenodactyli except for the fact that the latter project externally from the atrial wall while the former lie within the atrial wall. The reservoir duct and glands of adenodactyli are related to cocoon formation, and the production of abundant secretion by the reservoir of the accessory glands suggests the same function here, with the muscular coiled duct and valves regulating the supply of secretion. On the other hand, in stained preparations, what appeared to be sperms were often seen in the terminal vesicle of the female gland, but no great reliance can be placed on this without special selective staining. It is hoped that with the further study of living planarians the function of the accessory glands in this species will be more clearly understood.
Remarks. The following specimens from Dendy's collection in the British Museum have been sectioned and found to have the same internal structure as G. graffii. Externally they are very similar, and Dendy, in describing the external characters only, suggests that each one closely resembles G. graffii, the only differences between the species or varieties being slight variations in colour or markings. I therefore include in the species G. graffii the forms identified by Dendy as follows:—G. agricola, G. iris (in part), G. inequalistriata, G. graffii var. nodosa, G. graffii var. occidentalis, G. graffii var, wharekauriensis.
A number of species and varieties are tentatively included by me in the species graffii. As they were not among the British Museum specimens forwarded to me, I have only Dendy's description of the external features for comparison. Externally they all closely resemble G. graffii and such differences as do occur are not so distinctive as those which are found between some of the species and varieties now known to be graffii. As only one, or at the most two, specimens are recorded for each species or variety, the writer feels that there is insufficient grounds to warrant the formation of a new species or variety. I therefore tentatively include in the species G. graffii until such time as the type material can be examined, the forms identified by Dendy as follows:—G. fagicola (1900, p. 233, one specimen); G. gelatinosa (1895, p. 186, one specimen); G. hamiltoni (1895, p. 186, one specimen); G. jacksoniana (1897, p. 262, one specimen); G. graffii var. castanea (1900, p. 225, two specimens); G. graffii var. dorso-mar-
Fig. 1. Diagianmatic longitudinal sagittal of G. groffii.
Fig 2. Diagrammatic longitudinal sagittal section of A. horcesi.
Aden., adcnodactylus; b.p., peins buls; d.c., ciliated duct; d.s., seminal duct; f.at., female atrium; g.at., genital atrium; g.c., glandualt canal; m.at., male atrium; od., oviduct; os., ovisac; pe., pcins; re., reservoir; sh.g., shell gland; v., valve; v.d., vas deferens; v.m., muscular vesicle; v.s., seminal vescle.
morata (1900, p. 228, one specimen), G. graffii var. clintonis (1900, p. 228, two specimens); G. graffii var. ocellata (1900, p. 226, one specimen).
Von Graff (1899, p. 356) includes in G. graffii all the varieties then described—i.e., somersii, occidentalis and otiraensis. I have had no specimen of the variety somersii, but Dendy (1900, p. 227) in describing the variety nodosa which is now definitely graffii, says: “This variety comes very near to G. graffii var. somersii.” The variety occidentalis is graffii, but specimens of otiraensis from Dendy's collection have been sectioned and are entirely different internally from graffii and should not therefore be included in that species.
One of the earliest land planarians described from Dunedin is G. moseleyi Hutton (1880). Unfortunately no size is given in the description, but von Graff (1899, Pl. 6, Figs. 33–35) figures the specimen now in the British Museum. Very few markings seem to have remained (judging from the figure), but from Hutton's description and the general shape and size according to the figure, it is possible that G. moseleyi and G. graffii are the same worm; Dendy (1896) says: “Perhaps in the future it may be desirable to unite the several varieties of G. graffii which I have described, together with G. iris and the Dunedin form described by Hutton (i.e., G. moseleyi) under the one name G. moseleyi, which will then have to be regarded as a widely-spread species with numerous local varieties.” Dendy was right so far. Several varieties of graffii and iris (in part) have now been found to belong to one species G. graffii. Whether the name of that species will remain graffii or be changed to moseleyi can only be decided when the internal structure of the type moseleyi is known.
Artioposthia howesi (Dendy).
1900. Geoplana howesi Dendy, Trans. N.Z. Inst., vol. xxxiii, pp. 238–239. Locality. Numerous specimens were collected by Professor Marples at Duntroon, North Otago, New Zealand, at all times of the year. One specimen from the British Museum was found at Inver-cargill Bush.
External Characters. Dendy (1900, p. 238) gives the length in spirit as 24 mm., which is an average size, living specimens varying from 15 mm. to 32 mm. The dorsal surface is pale yellow, with three brown stripes and an orange anterior tip. The ventral surface is pale yellow with no markings. The three ventral longitudinal bands which Dendy describes in spirit have not been seen.
The three dorsal stripes consist of one narrow median stripe and two much broader bands, about half way between the median stripe and the margins. There is much more variety both in the form and the colour of the stripes than Dendy indicates. He gives the colour as dark brown, but actually it varies from bright tan to dark brown. Dendy also describes the stripes as solid bands of colour in which there are no speckles and none between the bands, this being one of the features which distinguish howesi from G. subquadrangulata. Actually alongside the typical howesi are always found some smaller forms which are generally similar to the larger ones except for the fact that the stripes of the small ones are composed of brown
speckles and are not so well-defined and solid-looking. These smaller worms have been sectioned and also examined in oil of wintergreen and are found to be immature. From the examination of a great variety of specimens at various times of the year, it would appear that the lateral stripes which in young forms are tan-coloured and are composed of speckles, gradually become darker and the speckles more numerous as the worms grow, until in the fully-grown worm the stripes are very dark brown, and the speckles have become so numerous as to run into each other and form continuous lateral bands.
The eyes are numerous and are arranged in a single row right round the anterior tip. The mouth is slightly nearer the posterior than the anterior end, and the genital pore is about half-way between the mouth and the posterior end.
Reproductive Organs. There is a common genital atrium (g.at.) into which the male duct opens anteriorly through a muscular penis (pe.), and the female duct opens posteriorly through a muscular process of similar length. From the dorsal wall of the atrium three adeno-dactyli project into the atrial cavity.
The paired ovaries are in the usual ventral anterior position, and from each a single oviduct goes back. Behind the atrium the two oviducts join to form a wide ovisac (os.), which gradually narrows and opens into the atrial cavity through a long muscular process. The ovisac contains sperms and mucus and receives the secretion from numerous glands on the ventral surface.
The testes lie below and slightly between the gut-diverticula, and extend from just behind the ovaries to the genital atrium. The vasa deferentia (v.d.) from each side join to form a short, narrow seminal duct (d.s.) which opens into the seminal vesicle. The seminal vesicle (v.s.) has two regions connected by a short, narrow duct. The proximal region is wide and ciliated, and contains sperms, the distal region is glandular and contains lumps of secretion and opens to the exterior by a short ejaculatory duct.
The adenodactyli (aden.) are of the usual type each with a glandular duct opening into the atrial cavity. Unlike those of A. triangulata (1937), there is no inner reservoir, but the duct enlarges to form a glandular cavity near the opening to the exterior.
Remarks. It is obvious that the classification of the land plan-arians cannot be based wholly on external markings, eyes, adhesive organs, etc., rather that it must be based primarily on the reproductive organs, though how much variation is to be allowed for seasonal changes is not clear.
The genus Artioposthia was created for those forms with adenodactyli, and three separate species have now been described for New Zealand. Miss Hyman (1931), however, thinks that the copulatory organs are unsuitable for classificatory purposes, and while stating that adenodactyli are absent from all American forms, doubts their taxonomic value. If adenodactyli are only a seasonal or sexual variation, then a regular examination of one species at short intervals throughout the year should help us to reach some definite conclusion
on this point. In both summer and winter, fully-grown specimens of A. howesi had adenodactyli, and it would appear as if they were here a definite regular part of the reproductive system. The writer is at present examining fortnightly collections of A. triangulata in an endeavour to decide whether adenodactyli are a constant feature of that species.
The writer records her thanks to Professor B. J. Marples for valuable suggestions and criticism.
Dendy, A., 1895. Notes on New Zealand Land Planarians, Part I, Trans. N. Z. Inst., vol. xxvii, pp. 177–189.
—– 1897. Notes on New Zealand Land Planarians, Part III, Trans. N. Z. Inst., vol. xxix, pp. 258–264.
—– 1900. Notes on New Zealand Land Planarians, Part IV, Trans. N. Z. Inst., vol. xxxiii, pp. 222–240.
Fyfe, Marion L., 1937. The Reproductive System of the Planarian Artioposthia triangulata (Dendy), Quart. Journ. Mior. Sci., vol. lxxx, pp. 99–126.
Graff, L. von, 1899. Monographie der Turbellarien, II, Triclada Terricola (Landplanarien).
Hutton, F. W., 1880. Additions to the List of New Zealand Worms. Trans. N. Z. Inst., vol. xii, pp. 277–278.
Hyman, L. H., 1931. Studies on the Morphology, Taxonomy and Distribution of North American Triclad Turbellaria, IV, Trans. Amer. Mior. Soc. Menasha, vol 1, pp. 316–335.