DECAPODA, 73 



in the markets at Nice. It is also found on the coast of the 

 department of France, called the Bouches-du-Rh6ne(l). 



Hymenocera, Latr. 



The two anterior feet terminated by a long hook with a bifid ex- 

 tremity, and composed of very short divisions. The two following 

 are very largej the hands, immovable finger, and superior thread of 

 the intermediate antennae are dilated, membranous, and almost foli- 

 aceous. The external foot-jaws are equally foliaceous, and cover the 

 mouth. 



The only species known is in the collection of the Museum 

 d'Histoire Naturelle, and was captured in the Indian Ocean. 



We now pass to subgenera, in which the claws present no remark- 

 able or insulated peculiarity. 



Sometimes the superior or intermediate antennae are only termi- 

 nated by two threads. 



The rostrum is usually short. 



Gnathophyllum, Latr. 



The Gnathophylla are the only ones which approach the Hyme- 

 nocerae in the size of their foot-jaws. The four anterior feet form di- 

 dactyle claws; the second pair is longer and thicker than the first. 

 Neither of the segments of the four is annulated(2). 



PoNTONiA, Latr. 



The four anterior feet, as in the two following subgenera, didac- 

 tyle claws, but the carpus is not annulated(3). 



Alpheus, Fab. 



The four anterior feet also terminated byadidactyle claw, but the 

 carpus of the second is articulated. The latter are shorter than the 

 former(4). 



(1) For the remaining species, see Risso, Hist. Nat. des Crust, de Nice; Leach, 

 Make. IJrit., XLI; and the Nouv. Diet. d'Hist. Nat., Ed. 11. 



(2) Alpheus elegans, Risso, Crust., II, 4; Desmar., Consid., p. 228. 



(3) Alpheus thyrenus, Risso, Crust., II, 2; Astacus thyrenus, Fetag., V, 5; Des- 

 mar., lb., p. 229. 



(4) Alpheus malabaricus. Fab., and probably some other species, with which, 

 however, I am not sufficiently acquainted. See Desmar., Consid., p. 222, 223. 



Vol. III.-K 



