268 SUBANTARCTIC IS1.ANDS OF NEW ZEALAND. [Oligochaela. 



Fam. MEGASCOLECIDAE. 



Subfam. ACANTHODRILINAE. 



NoTiODRiLUS, Michaelsen, 1899. 



Notiodrilus fallax, sp. nov. (Plate XI, figs. 16, 17.) 



Tliree individuals. 



Colour. — Dark chocolate-brown (in formol) ; pigment extends over the ventral 

 surface. 



Dimensions. — The largest, which is a good deal contracted, is 175 mm. in 

 length and 11 mm. in diameter; no doubt, in life it would have reached at least 

 200 mm. 



Tlie prostomium is epilobic about half, with a transverse groove, but no marginal 

 extensions backwards. The anterior segments are biannulate, the limits quite dis- 

 tinct ; the post-clitellar segments are triannulate. 



Chaetae. — In the mid-body ab = cd ; be about \\ ah ; dd = Qab ; aa = 2 ah — 

 that is, > he. In the preclitellar region ah <.cd ; aa = be. 



The clitdlum, which is very dark brown in colour, is saddle-shaped, and ceases 

 at line b ; it covers segments 14-19, the ventral surface of which is pale yellowish. 



Genitcd Pores, <&c. — The spermatic groove is concave ventrally, and allows 

 both chaetae a and b to be seen in each of the segments 17, 18, and 19. Sperma- 

 thecal pores are invisible externally, but lie in the usual position. Nephridiopores, 

 as seen in section, are just below chaeta c. 



Internal Anatomy. 



The septa behind segments 9-12 are very thick, and that of 13 nearly as thick. 



The dorsal vessel is double throughout ; hearts in 10-13. 



The gizzard is large, in the 6th segment ; oesophageal glands in 13 and 14. 



Nephridia very small, in a single row ; extend only from 6 to c ; those of the 

 4th segment are large pepto-nephridia, but whether they open into the gut or not 

 I did not ascertain, as the body is too contracted to allow me to trace them by dis- 

 section. 



The testes and ovaries are on the anterior wall of their segments: sperm-sacs 

 in 9 and 12 ; both are large, saclike, and but feebly racemose ; there are none in 

 the intervening segments. 



Prostates compressed, the tube being a good deal contorted, so as to form a 

 more compact mass than is common in the genus (Plate XI, fig. 17). Each is 

 limited to its own segment ; has a narrow duct, which passes transversely across 

 the body-wall for a distance equal to about half the breadth of the gland, to open 

 to the exterior in the line b. No penial chaetae are recognisable, and no " arcuate " 

 muscles are present in these segments 



Spermathecae. — Two pairs, in the 8th and 9th segments ; each has a couple 

 of glomerulate diverticula opening into the duct, close to the body-wall, on the 

 anterior and posterior aspects respectively (Plate XI, fig. 16). 



Locality. — Snares Island ; in company with N. haplocystis. 



