288 CRUSTACEA. 



GENUS LISSOCARCINUS, White. 



Carapax suborbicularis, frante utraque margine antero-laterali simul 

 arcuatis, fronts producto, sive integro sive medium emarginato. Artir 

 culus antennae, externce \rnus fere longitudinalis, hiatum orbitce occu- 

 pant, processu angusto articulum sequentem e orbitd prcecludente. 

 Pedes nudi, antici breves, brachio ultra carapacem vix saliente, manu 

 perbrevi. 



Carapax suborbicular, the front and either antero-lateral margin 

 forming an arcuate outline, front produced, either entire or emar- 

 ginate at middle. Feet nude, anterior short, arm hardly projecting 

 beyond the carapax, or not at all so, hand very short. First joint 

 of outer antennae nearly longitudinal, filling the orbital hiatus, a 

 narrow process separating the following joint from the orbit. 



We have modified the generic characters of this genus, established 

 by Adams and White, in order that it may include our species, which 

 is evidently closely related to the L. polybioides. 



The carapax is smooth and has a hard-looking surface, and the 

 shell of the legs is equally thick and shining. The very short arm 

 and hand, as well as the character of the front, distinguish it from 

 any of the Charybdes. The lateral margin is thin and a little re- 

 flexed. The part of the hand posterior to the fingers is not longer 

 than its vertical height; and it has not the costate appearance of most 

 of the Thalamitse. Moreover the species are very narrow, the follow- 

 ing but little broader than its length, and the polybioides even nar- 

 rower than long. 



The third joint of the outer maxillipeds is transverse in the poly- 

 bioides, but a little oblong in the orbicularis. The only marking on 

 the surface of the carapax in each is a straight line extending inward 

 from the posterior lateral lobe or tooth. 



Litsocarcinus, WHITE, Samarang Crust., p. 45. 



LISSOCARCINUS ORBICULARIS. 

 Carapax paululo latior quam longus, Icevissimus, nitidus, fronte medium 



