260 SPECIFIC DESCRIPTION. 



point. The dorsal surface is tolerably smooth, 

 exhibiting but faintly the markings of the internal 

 viscera. The 'eyes are small, and reach but little 

 beyond the orbital margin. The external 

 antennas have the first joint fused with the cara- 

 pace, the second and third compressed and arcu- 

 ate, and terminate in a smooth flagellum. 



The first pair of pereiopoda are moderately 

 long, having the meros triangulate, the upper angle 

 forming a prominent carina, that extends along 

 but terminates abruptly a little short of both 

 extremities of the joint ; the carpus is tricarinated ; 

 the propodos is laterally compressed, and forms 

 about half the length of the limb, and is about 

 one-third its breadth. The dactylos is slightly 

 curved and slightly serrated on the inner margin, 

 and antagonises at the extremity with the pro- 

 duced propodos. The second pair of pereiopoda 

 are nearly as long as the first, but much more 

 slender, having the meros and propodos subcari- 

 nated. The three posterior pairs are shorter. 

 The pleon is small and narrow, the second and 

 third segments being the broadest; while the 

 seventh is abruptly narrower than the sixth, and 

 forms a triangular plate. The female differs 

 from the male in being more protuberant over 

 the stomachal region, and consequently the ros- 



