CUMACEA FEOM THE COPENHAGEN MUSEUM. 379 



DiASTYLOPSIS ELOiS'GATA, sp. n. (Plate XXXVII. figs. 1-12.) 



Bescriftion of adult Female. — Total length 9-2 mm. 



Carapace a little more than one-fourth of total length, compressed, its vertical height 

 less than half its length ; dorsal edge very slightly arched. Pseudorostrum straight, 

 acute, slightly raised so as to form a very ohtuse angle with the dorsal edge, about 

 one-fifth of total length of carapace. Antennal notch slightly marked. Antero-lateral 

 corner rounded and rather coarsely seriated. Ocular lobe with a minute terminal 

 tooth projecting above the dorsal outline of the carapace. No distinct eye. Surface 

 of carapace smooth. 



The five leg-bearing somites are all distinct ; the second is much longer than the 

 first ; the third and fourth are strongly expanded backwards at the sides, and a wide 

 interval is left between the second and third pairs of legs. 



The abdomen is about as long as the cephalothoracic region, rather slender, the fifth 

 somite about twice as long as deep ; first somite with a prominent, backwardly-curved 

 tooth in the middle of the sternal surface ; fifth somite with the postero-lateral angles 

 spiniform. 



Telson a little shorter tban the last somite, its post-anal part much narrowed, 

 the width at the level of the proximal pair of lateral spines being about one-eighth 

 of its length ; there are about eight pairs of short lateral spines, occupying about 

 two-fifths of the lateral edge ; the terminal spines are short. 



Antennules with the first segment of the peduncle stout, expanding distally, shorter 

 than the other two together ; the second much stouter than, and more than half 

 as long as, the third ; the outer fiagellum composed of three and the inner of two 

 segments, with perhaps a minute terminal segment in each case. 



The antenna is composed of three segments. 



The mouth-parts are of normal type. The mandible has an elongated body and 

 about twelve spines on the inner edge. The palp of the maxillula is bisetose. The 

 basis of the third maxilliped is twice as long as the distal segments together, hardly 

 expanded distally, carrying a well-developed exopod. 



The first legs extend beyond the tip of the pseudorostrum by little more than the 

 terminal segment ; the basis is longer, by more than one-third, tl:ian the distal segments 

 together, and has a row of denticles on its lower surface and a tooth at its distal inner 

 corner ; the carpus and propodus are subequal, and each a little longer than the 

 dactylus. 



The second legs have the basis a little less than one-third longer than the distal 

 segments together, with a small tooth at its distal inner corner; the ischium and 

 merus have the inner edge produced distally as a slight tooth ; the merus is two- 

 thirds as long as the carpus and a little shorter than the propodus and dactylus 

 together. 



