CUMACEA— CALMAN. i53 



Stebbing, following a suggestion made by Zimmer (1908, p. 190) but afterwards 

 abandoned by him (1913, p. 478), has placed this species in the genus JDiastylojysis- 

 In Mr. Stebbing's classification Diastylopsis is distinguished from Diastylis mainly by 

 the wide separation of the second and third pairs of legs in the adult females of the 

 former genus. In this respect D. neozealanica and D. insularum do not differ from a 

 number of species included by Stebbing in Diastylis, and their exclusion from 

 Diastylopsis leaves that genus more sharply delimited. 



20. Colurostylis lemurum, n. sp. Figs. 7, 8. 



Occurrence. — Station 135. Spirits Bay, near North Cape, New Zealand. Plankton, 

 3 metres depth. Six females (inch holotype), one male. 



Description. — Ovigerous female. Total length 4 mm. 



Carapace rather more elongate than in C. pseudocuma and having the pseudo- 

 rostrum, in most specimens, distinctly longer and more acute. There is a strong 

 oblique ridge running forwards and downwards on the side of the carapace ; in front of 

 this a weaker ridge, running more horizontally, defines a somewhat depressed area 

 occupying the lateral region of the frontal lobe ; these ridges unite with a narrow 

 U-shaped ridge on the dorsal surface. There is a strong ridge running parallel with 

 and close to the hind margin of the carapace. Between the ridges the surface is pitted 

 with shallow depressions, less marked than those of C. pseudocuma. The ocular lobe 

 is large, about twice as wide as long, with visual elements apparently well-developed, 

 in four groups, without pigment, and without conspicuous corneal lenses. 



The separation of the second from the third pair of legs, while well-marked, is not 

 quite so extensive as in C. pseudocuma. The third and fourth free somites are more 

 firmly united than in that species, being only defined from each other by a superficial 

 groove. 



Telson a little less than half the length of the last somite, shaped as in 

 C. pseudocuma. 



Antennules with the third segment of peduncle narrower and longer than second. 

 Antennae apparently consisting of four segments, each bearing a single seta. 



Branchial apparatus with about ten finger-shaped lobules. 



First legs rather stout, distal segments longer by one-third than the basis, 

 propodus nearly equal to carpus and twice as long as dactylus. 



Second legs with basis nearly as long as distal segments together, dactylus less 

 than one and a half times as long as propodus. 



Exopods of third and fourth legs less than one-third as long as the basis. 



Peduncle of uropods from twice to two and a half times as long as last somite, 

 endopod a little longer than exopod and less than two-thirds as long as peduncle ; 

 proximal segment of endopod three-fourths of length of distal segment or a little more ; 

 peduncle and exopod serrated on inner edge, endopod with a close-set row of fine setae. 



