Oligochaeta.] SUBANTARCTIC ISLANDS OF NEW ZEALAND. 263 



Fam. HAPLOTAXTDAE. 

 Pelodrilus, Beddard, 1891. 

 Pelodrilus tuberculatus, sp. nov. (Plate X, figs. 12-14.) 



A considerable number of these small and characteristically coloured worms 

 were collected both on the Auckland and on the Campbell Islands. 



Dimensions. — Length, from 40 mm. to 70 mm., by 2 mm. in diameter. The seg- 

 ments are well marked, and number from 100 to 110 in those examined. The body is 

 somewhat flattened, especially towards the posterior end. A lateral line is very 

 evident. 



Colour. — Except for the anterior preclitellian end, which is opaque-white, the 

 body is bluish-grey, owing to the transparent wall allowing the intestinal contents 

 to be seen. The clitellum is pale yellowish-brown in preserved worms, though in 

 life it is yellow. A remarkable feature about the body-wall is the thick cuticle, 

 which gives a shining appearance to the worm, so that it bears a resemblance to 

 certain Enchytraeids. In specimens preserved in alcohol the wall is less translucent, 

 but in formol this character is retained. 



The prostomium is small and rounded, not as long as the segments 1 and 2 

 together. 



The chaeiae are in four couples, all sigmoid. The individual chaetae are, of 

 course, quite close together. The dorsal gap (dd) is less than the ventral gap (aa), 

 which is in its turn less than the lateral gap (be). In the anterior part of the body 

 the dorsal and ventral chaetae are of the same size, but in the mid and hind body 

 the dorsals are only two-thirds the length of the ventrals. 



The ventrals are absent from the 12th segment in the mature worm. 



The clitellum is confined to the dorsal and lateral portions of the segments 

 J 11, 12, and 13, though in some cases nearly the whole of the 11th is glandular 

 dorsally. On the ventral surface of 12 is a pair of latero-ventral glandular ridges 

 in line with the ventral chaetae ; these ridges are broad and low, and may extend 

 slightly on to 11 as far as the chaetae. These ridges carry the two pairs of male 

 pores, and no doubt function as prostate glands ; they may be termed the copu- 

 latory glands (text figure, p. 264, and Plate X, fig. 12). 



Tubercula puhertatis are present in several segments. They have the form of 

 paired or median, rounded, slightly prominent papillae, which are very evident 

 as white spots in specimens preserved in alcohol. They are somewhat variable in 

 number, but are usually situated as follows : Segment 7, a pair of closely approxi- 

 mated or even median papillae ; segment 8, a pair of closely approximated or even 

 median papillae (these are placed behind the chaetal zone) ; segment 9, paired, 

 mediad and posterad of ventral chaetae, also a pair dorsad of the chaetae in the 

 chaetal zone ; segment 10, paired, mediad and posterad of ventral chaetae, also 

 a pair dorsad of the chaetae in the chaetal zone ; segment 13, pair, mediad of the 

 chaetae ; segment 14, pair, mediad of the chaetae. More rarely there is a median 

 papilla on the 15th segment also. In one specimen the number was greater, as a 

 series of post-chaetal papillae of smaller size, close to the posterior margin of 10, 13, 

 and 14, were present. I am not aware that such tubercula have been recorded in 

 the genus. 



