CUMACEA FKOM THE COPENHAGEN MUSEUM. 381 



DiASTYLOPSis CRASSiOR, sp. D. (Plate XXXVII. figs. 13-18.) 



Description of adult Female. — Total length 925 ram. 



Closely resembling D. elongnta. The slightly curved dorsal outline of the carapace 

 is continued without a break by the upper edge of the pseudorostrurn. The ocular 

 lobe is not prominent dorsully, and has no tooth. The pseudorostrurn is less acutely 

 pointed than in D. elongata. 



Abdominal somites much stouter than in I), elongata, the fifth somite less than one 

 and a half times as long as deep. First somite without any median tooth on the 

 ventral side (only in one specimen a minute median denticle was observed), but with 

 two ventro-lateral rows of denticles. Postero-lateral angles of third, fourth, and fiftii 

 somites spiniforra. 



Telson much less narrowed distally than in D. elongata, its width at the level of the 

 proximal pair of spines nearly one-fourth of its length ; there are seven or eight spines 

 on each side and the terminal spines are short. 



The antennules are relatively a little longer than in B. elongata. The mouth-parts 

 show no differences of importance. 



The first legs ha'c the spines on the lower surface of the basis stronger and more 

 numerous than in D elongata. The basis of the second legs is little shorter than the 

 distal segments together and has some teeth on its lower surface and outer edge and a 

 strong tooth at its distal inner corner ; the ischium is produced on the inner side into 

 two and the merus into three strong teeth ; the merus is a little more than half as long 

 as the carpus, and equal to the propodus and dactylus together. 



The succeeding pairs of legs are stouter aud longer than in D. elongata. The tooth 

 at the distal end of the basis in the third and fourth is strong and, in some cases, 

 bifid. 



The peduncle of the uropods is twice as long as the telson and has six spines, much 

 longer than those of Z*. e/ow^aiff, on its inner edge; the exopod is distinctly longer 

 than the endopod, which is about two-thirds as long as the peduncle; the spines on 

 the inner edge of the peduncle are longer than in D. elongata. 



Remarks. — This species is very closely allied to, but I believe distinct from, I), elongata, 

 in company with which it occurred. It differs from that species in the stouter abdomen 

 (which is very conspicuous when specimens of similar size are compared), in the 

 very different spinous armature on the under side of the first abdominal somite, 

 in the form of the telson, and in the stronger spines on the legs, especially on the 

 second pair. 



Occurrence. — New Zealand, " Lyttleton Harbour, 1-5 fathoms, H. Suter Coll., 8/97." 

 Copenhagen Museum. Co-types in British Museum. 



VOL. JVHI. — PART IV. No. C. — February, 1911. 3f 



