290 RATHBUN 



Genus Discias gen. nov. 

 Characters of the family. 



DISCIAS SERRIFER sp. nov. 



Adult female. — Carapace stout, somewhat compressed, the height 

 greater than the width and more than two thirds of the length ; 

 smooth, punctate. Rostrum resembling that of Atya^ 

 deflexed, depressed, with a smooth median carina ; 

 lateral margins thin, finely denticulate ; extremity acute, 

 not reaching the end of the first antennular segment. 

 A large spine at the lower angle of the orbit. Antero- 

 lateral angles obliquely rounded, unarmed. Eyes large. 

 Second and third antennular segments very short, the 

 third a little the longer ; the flagella are broken off ; 

 the inner one is at least as long as the peduncle. The 

 Fig. 2 , antennal peduncle extends to the end of the first seg- 

 Disctas ser- j^gnf of the antennular peduncle ; scale oval, exceeding 



rijer, ^^ antennular peduncle by a distance equal to the 



maxilliped ^. j 



/w j_N length of the last two segments of that peduncle; it 



has a inidrib, its outer margin is thin and w^ithout a 



spine, inner margin finely denticulate ; flagellum half the length of 



the body. 



The outer maxilliped does not quite reach the end of the antennal 

 scale ; the terminal segment is narrowly oval and its 

 margins are spinulous. 



The first pair of chelipeds exceed the scale by about 

 the length of the fingers ; the merus is triquetral and 

 widens toward the distal end which is hollowed out and 

 at its lower angle articulates with the carpus. The carpus 

 is reduced to a flat round plate articulated against the lower 

 surface of the propodus, a proximal prolongation of which ^ . '. 

 conceals it. The carpus is not visible in Fig. 3. The serrifer, 

 propodus is oblong, narrowest at the proximal end, the chela of 

 palmar portion less than twice as long as broad and having the first 

 on its upper surface a broad longitudinal depression ; pereiopo 

 pollex slender, strongly curved, fitting closely against the 

 dactylus which is subcircular or broadly ovate, slightly obtusely 

 pointed at the extremity. 



The chelipeds of the second pair fall short of the end of the palm of 

 the first pair ; they are much smaller ; the merus is similar to that of 



