of the Division Hyperina. 7 



Brachyscelus. 



Cephalon anteriorly rounded. Eyes occupying the lateral 

 walls, which encroach upon the inferior margin. Pereion not 

 distended, nearly as deep as the cephalon, and not wider. Pleon 

 nearly as broad as the pereion ; fourth and fifth segments fused 

 together. Antennas obsolete or very rudimentary. Oral ap- 

 pendages membranous and rudimentary. Gnathopoda com- 

 plexly subchelate. Pereiopoda having the basa of the three 

 posterior pairs largely developed ; fifth pair having the remain- 

 ing joints not obsolete. Pleopoda biramous. Telson single. 



Brachyscelus crusculum. 



Female. — Animal round and smooth. Cephalon anteriorly 

 depressed, rounded. Oral appendages consisting of two small, 

 narrow, pointed foliaceous plates, having a quadrate mem- 

 branous plate centrally placed behind them. First pair of gnatho- 

 poda short, having the carpus broader than long, inferior angle 

 anteriorly produced, deeply serrated upon the anterior and in- 

 ferior mai-gins, teeth upon the inferior margin posteriorly ser- 

 rated; propodos arcuate, inferior margin serrated; dactylos 

 short, slender, and sharp. Second pair resembling the first, but 

 slightly longer ; carpus longer than broad, having the anterior 

 margin directed obliquely forwards, and equal to the length of 

 the carpus. First pair of pereiopoda simple, slendei', finely ser- 

 rated upon the posterior margin of the meros, carpus, and pro- 

 podos. Second pair like the first, but longer, and serrated only 

 upon the propodos. Third pair of pereiopoda having the basos 

 long-quadrate, slightly tapering towards the distal margin, 

 posterior margin slightly arcuate; ischium articulating at the 

 extremity of the basos ; remaining joints longer than the basos. 

 Fourth pair having the basos broader than the preceding joint, 

 posteriorly dilated, and tapering to the distal extremity, where it 

 articulates with the ischium ; remaining joints not quite as long 

 as the basos ; the anterior or flexible margin finely serrated, ex- 

 cept the dactylos. Fifth pair having the basos ovate, not so 

 broad as that of the fourth pair; remaining joints about half the 

 length of the basos ; carpus having the anterior or flexible 

 margin finely crenulated ; dactylos small, hooked, and sharp, 

 apparently immobile. Antepenultimate and penultimate pairs 

 of pleopoda articulating at the distal lateral extremity of the 

 coalesced fourth and fifth segments : antepenultimate pair having 

 the rami styliform, with the approximal margins serrated ; pen- 

 ultimate having the rami subfoliaceous, lanceolate; ultimate 

 having the rami foliaceous, ovate. Telson triangular, longer 



