376 DE. W. T. CALMAN ON NEW OB EAEB 



distal a little longer than the proximal, with a slender terminal spine, one spinule on 

 the inner edge of the first and two on the second segment. 



Adult Male. — Total length 1-7 mm. 



The dorsal outline of the carapace, seen from the side, is more evenly arched than 

 in the female, not sloping in front, where the dorsal surface is convex from side to side 

 and projects above the dorso-lateral crests. The pseudorostrum is a little more obtuse 

 than in the female, and its upper edge slopes downwards. The ocular lobe is more 

 prominent. The crests of the carapace and of the leg-bearing somites are disposed as 

 in the female. 



The antennffi reach only to the hinder edge of the carapace, by which, in the natural 

 position, they are wholly concealed. 



The third maxilliped has a well-developed exopod. The first legs are a little shorter 

 than in the female. All the legs, except the last pair, have exopods. 



The uropods are relatively a little longer than in the female, the difference in length 

 of the rami is less, and their terminal spines are longer ; the inner edge of the endopod 

 has two spinules on the proximal segment and three on the distal. 



Eemarks. — This species differs greatly in general appearance from the other 

 members of the genus ; the short and stout cephalothoracic region, the presence of 

 only a single pair of ridges on the carapace, and the reduction of the interval between 

 the second and third pairs of legs in the female are all well-marked distinctions. 



Occurrence. — Gulf of Siam, " Koh Kam, 5-10 fathoms, 2/00," "Between Koh 

 Mesan and Cape Liant, 5-8 fathoms, 7/2/00." Th. Mortensen Coll. Japan, " 33° 

 10' N., 129° 18' E., 40 fathoms, 7/9/97, Suenson Coll." Copenhagen Museum. 

 Co-types in British Museum. 



Pakadiasttlis lokgipes Calm. 



Paradiastylis longipes Caiman, Cumacea of Siboga Expedition, p. 21, figs. 4a-i (1905). 

 Occxhvrence. — Gulf of Siam, " Koh Kam, 5-10 fathoms, 2/00," " Between Koh 

 Mesan and Cape Liant, 5-8 fathoms, 7/2/00." Th. Mortensen Coll. Copenhagen 

 Museum and British Museum. 



Genus Colukostylis, gen. nov. 



Pleural plates of third and fourth free thoracic somites expanded backwards, third 

 legs separated from second in adult female ; telson very small, flattened, without 

 spines ; third maxillipeds with exopods in both sexes ; third and fourth legs with 

 vestigial exopods in female ; two pairs of biramous pleopods in male ; endopod of 

 uropods of two segments. 



Type-species C. pseudocuma, sp. n. 



In addition to the form and size of the telson, the general form of the body in the 



