280 SUBANTARCTIC ISLANDS OF NEW ZEALAND. [Oliguchaela. 



The prostates are flattened, compact, and lobulated, occupying the lateral part 

 of the 18th segment. The short wide duct, as it passes through the body-wall, re- 

 tains its own muscular coat, and is thus easily traced to the pore (Plate XI, fig. 24) ; 

 in this respect it differs much from the prostate duct of Diporochaetn. 



In spite of the external lobate form, the prostate is essentially a cylindrical 

 tube, closely undulating and compressed, so that the waves are in contact. There 

 is a central canal traversing the gland, with a uniform diameter throughout ; it 

 is lined by a flat epithelium with large nuclei, and receives short branches at 

 intervals along its course ; into these branches the necks of groups of gland-cells 

 discharge their secretion (Plate XI, figs. 25, 26). (Cf. Sweet, pi. 15, fig. 17, illustrating 

 P. inter medius). 



The ventral chaetae are replaced by long slender " penial chaetae." 



The ovaries are very large and project upwards above the oesophagus, and the 

 strings of ova fully occupy the segment. 



The two spermathecae lie in segments 8 and 9 ; each is a somewhat pyriform 

 ampulla, with a duct nearly as long as itself, into which opens, about half-way along 

 its course to the body-wall, a single small subglobular diverticulum (Plate XI, 

 fig. 23). The pore is close to the nerve-cord. 



Locality. — Auckland Islands : (a.) Adams Island ; among the roots of Pleuro- 

 phyllum in Fairchild's Garden; (Aston; W. B. B.). (6.) Adams Island ; 1,350 ft.; 

 (Speight), (c.) Port Ross; (W. B. B.). [d.) 200ft. above the Watering Creek, at 

 Camp Cove ; (W. B. B.). Those collected by myself were found both in February 

 and November. 



Remarks. — The genus Plutdlus is a characteristic Australian worm, for about 

 fifty-five out of the sixty species occur on that continent. Possibly the Indian 

 species should be removed from the genus. The present species differs from any 

 of the known species, though it is clearly related to some of the Australian worms. 

 Some years ago I described P. lacustris* from Lake Manapouri, which Michaelsenf 

 has transferred to the genus Pontodrilus, which differs from Plutellus only in {a) the 

 absence of nephridia from the anterior segments, and (h) in the absence of a gizzard, 

 while all the species are littoral with the exception of P. lacustris. It was on 

 account of the last peculiarity that I placed the species in Plutellus, at the same 

 time noting its resemblance to Pontodrilus, and suggesting that its aquatic habit 

 had led to the disappearance of the gizzard and anterior nephridia. However 

 that may be, the present species is the first terrestrial species of Plutellus that 

 has been recorded from the New Zealand area. It appears to be allied pretty 

 closely to P. tuberculatum, Fletcher,J from New South Wales, from which it 

 differs, however, in the disposition of the tubercula pubertatis, which in that 

 species are stated to be on the first annulus of segments 17-22 ; also in the 

 chaetal formula. 



In discussing the geographical relations of the earthworm fauna of these islands 

 (p. 255;, I have suggested the manner in which this species may have been intro- 

 duced into the Auckland Islands. 



* Benham, " Some New Species of Aquatic Oligochaeta from New Zealand," Proc. Zool. Soc, 1903, 

 ii, p. 228. 



t Michaelaen, Die Fauna S.W. Austral., p. 160. 



j Fletcher {Noloscolex tuberculalus), Proc. Liun. Soc. N.S.W., ser. 2, vol. ii, p. 611, 1887. 



