288 Transactions. — Zoology. 



complete circle of short, sessile, globular diverticula, hiding 

 the duct when viewed in situ. 



Plagiochseta montana, n. sp. 



Locality. — In bush soil near Lake Thompson, 1,100 ft. 

 above sea-level, on the track from Lake Te Anau to George 

 Sound. They were collected by Mr. Mackenzie during the 

 formation of this track. 



Dimensions. — The collection contains a considerable num- 

 ber of individuals, ranging from 36 mm. by 5 mm. up to 

 190mm. by 12 mm. Of these only a few are mature, and the 

 smallest possessing a clitellum is 140 mm. by 8 mm. A speci- 

 men measuring 182 mm. contains 145 segments. The body is 

 rather broader than high. 



Colour. — Brick-red, browner anteriorly, with a brown 

 clitellum. The chastae are inserted in white rings girdling 

 the segments. 



The prosiomium is epilobic, with a posterior groove half- 

 way along the 1st segment. 



The chcetce are about thirty-six to forty per segment, not 

 in couples, but form a right and left series on each side, sepa- 

 rated by a dorsal and ventral gap of about three times the 

 interchaetal gaps, which, as in other species, are by no means 

 constant in their width. The number of chaetae diminishes 

 somewhat, but not materially, anteriorly. I counted thirty- 

 two on segment 4 and only twenty-lour on segment 11. 

 As usual, the ventral chaetae on the hinder clitellar segments 

 are rather more widely spaced than elsewhere. 



The clitellum covers segments 14 to 20, the limits of the 

 organ being very distinct. It is incomplete ventrally, ceasing 

 at about the level of the porophores. 



The large porophores are connected by a " spermatic 

 ridge." The body here bulges out laterally and is depressed 

 mesially, as in other species, possessing " transverse muscles " 

 in the 18th segment. The male pore is on a slight papilla. 

 The three pores are in line with the gap c/d. Chaetas a and d 

 are present on these three segments, but b and c are absent. 

 The oviducal pores lie in front of the gap a/b ; the sperma- 

 thecal pores in front of the chaeta d, in the intersegmental 

 furrows 7/8 and 8/9. 



Dorsal pores are evident behind the clitellum. 



Internal Anatomy. 



There are eight stout septa behind segments 9 to 16 

 those of 10th, 11th, and 12th segments are especially stout. 

 All are much thicker than in P. rossii. 



The dorsal vessel is double up to the 4th segment ; the two 

 are connected by short transverse vessels praeseptally. The 



