276 SUBANTARCTIC ISLANDS OF NEW ZEALAND. [Oligochaeta. 



The male pore is on a slight papilla on the 18th, just outside chaeta h. 

 The oviducal pores are clearly visible in line b, on the usual segment. 

 Spermathecal pores, two pairs, at 7/8, 8/9, are also very distinct, owing to their 

 pale colour, just outside b. 



Internal Anatomy. 



The dorsal vessel is double ; the last heart in the 13th segment. 



The nephridium is small and difficult to trace in sections ; it is entirely limited 

 to the prechaetal portion of the segment, and the tube is " tufted " at the level of d 

 and e ; but I am not quite sure at which level it opens. 



The gizzard may be said to be " absent," and in a dissection would be over- 

 looked ; but in sections one may detect a minute vestige in the 6th segment. The 

 wall is no thicker than that of the oesophagus immediately behind it, but the muscu- 

 lature is slightly better developed, and it is recognisable by the absence of villi on 

 the inner surface (Plate XI, fig. 18). 



The oesophagus is dilated in segments 14, 15, and its wall lamellate ; it is also 

 thick-walled ; though narrow in 17th to 19th, the gut suddenly dilates again, the 

 wall becomes thin, and the intestine commences in the 20th segment. 



Testes and ovaries in the usual position ; two pairs of sperm-sacs, in 9 and 12, 

 racemose. The prostates are tubular. The ovary large. 



Two pairs of spermathecae, in 8, 9. The ampulla is more or less ovoid ; the duct 

 wide and short, and receives two diverticula, tubular in form — one comes off anteriorly, 

 close to the body-wall, the other posteriorly, a little further from it (Plate XI, 

 fig. 20). 



Locality. — Snares Island. 



Remarks. — The occurrence of so typical a New Zealand genus on the Snares 

 is, of course, just what one would expect. The species comes near P. lateralis, 

 Benham,* from which it differs in the practical absence of a gizzard and in the 

 less number of chaetae. 



I cannot here discuss Michaelsen's recent proposal (1909) to subdivide this 

 genus. 



Leptodrilus, gen. nov. 



In 1904 I described a species of worm from one of the southern islands under 

 the name Rhododrilus leptomerus,^ which, resembling R. cockayni in most of its anato- 

 mical features, presents the very remarkable character of having the male pores 

 on the 16th segment instead of on the 17th, which is the generic character for Rho- 

 dodrilus. In order to emphasize this fact, I deem it desirable to separate this and 

 another species from Rhododrilus, as a new genus. 



Leptodrilus leptomerus, Benham. (Plate XI, fig. 21.) 



1905. Rhododrilus leptomerus, Benham, Trans. N.Z. Inst., xxxvii, p. 291. 



Of this species, which was originally collected by Dr. Cockayne, I have now 

 a good series, both from the Auckland Islands and from Campbell Island. In the 

 latter place it seems very common, judging from the number received by me since 



* Benham, Trans. N.Z. Inst., xxxv, p. 282, 1903. 

 t Benham, Trans. N.Z. Inst, xxxvii. p. 291, 1905. 



