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Show 1885.] NEW-ZEALAND EARTHWORMS. 811 these specimens in some detail, and venture to offer to the Society an account of their structure which will, I hope, help to fill up a gap in our knowledge of the anatomy of Earthworms ; at present, beyond a few short descriptions of some six species of this genus, the anatomy of Acanthodrilus is entirely unknown. I have endeavoured in the present communication to treat of the structure of this genus in as thorough a fashion as possible, and have taken as my models the excellent memoirs of M . Perrier on Crochata1 and Pontodrilus2. The anatomy of all three species will be dealt with together, and will form the second part of this paper ; the first part contains some remarks upon the genus and a brief description of three new species. PART I. The genus Acanthodrilus was instituted by M. Perrier in his ' Recherches pour servir a l'histoire des Lombriciens terrestres.'3 It belongs to his group " Postclitelliens," inasmuch as the male generative openings are situated behind the clitellum. The structural characters which serve to distinguish this genus from others are:-The presence of four male generative openings, each of which is furnished with a bundle of long, peculiarly modified penial seta3, enclosed in a special muscular sac, the ends projecting through the apertures : there is furthermore a prostate gland in connection with each of these apertures ; the vasa deferentia remain distinct from each other, and pass down the body from their anterior funnel-shaped internal apertures to their external apertures as four distinct tubes. The seta? are disposed in pairs as in Lumbricus. M. Perrier described three species-A. oblusus and A. ungulatus from New Caledonia, and A. verticillatus from Madagascar. A fourth species of this genus was collected in Kerguelen during the Transit-of-Venus Expedition, and described by Prof. Lankester4 under the name of A. kerguelenensis. More recently Dr. Horst has recorded the structural characters of two large species from Liberia, which he has named respectively A. buttikoferi and A. schlegelii3. Finally, I have myself described a seventh species from the Cape of Good Hope, under the name of A. capensis6. I shall take the opportunity presently of making some remarks upon the structural characters of these in connection with the new species to be recorded in the present paper. Little or nothing is known about the New-Zealand Earthworms ; pnd, so far as I am aware, there is no anatomical description of any one of the species, some seven in number, which have been recorded by Baird and Button 7 from this locality. Captain Hutton, C.M.Z.S., has briefly described four species of 1 Arcb. d. Zool. Exp. t. iii. 2 Arcb. d. Zool. Exp. t. ix. 4 Phil. Trans, extra vol. 1879. 3 Nouv. Arch. d. Museum, t. viii. 5 Notes from Leyd en Museum, vol. vi. 6 Proc. Koy. Phys. Soc. 1884-85, p. 309. 7 Proc. Linn. Soc. vol. xi. p. 96. |
