DECAPODA. 179 



notched; two teeth on tin; interior margin, and two others 

 widely separated on each lateral muscle ; the posterior largest 

 and fphuform, and situated above the origin of the posterior 

 feet, 



Tin- sea coast of the wot em department* of France produces 

 some other species, which belong to the genus Ebalia, Leach *. 

 All the remaining ones arc l'n*m India and America. 



Some fossil Leucosiro are found in the East Indies. Three 

 species have b . n d-M-iil-d by M. Desman st. two of which, 

 according to him, are true Leucosice, Leach, and which are 

 now living in tin- same countries, and peculiar to them. 



Our fifth section, that of the TRIGONA, is composed of those species 

 whre shrll i> usually triangular or subovoid, nurrowed before into a 

 point or kind of beak, generally uneven and rough, with lateral eyeg, 

 The interval comprised between the antennae and the buccal cavity 

 i* ahvay* nearly square, as long, or almost as long, as broad. The 

 (laws, ut least those of the males, are always large and elongated. 

 '!' he following feet are very long in a great number, and sometimes 

 the two last even differ in form from the preceding ones. The third 

 joint of the external foot-jaws is always nearly square or hexagonal, 

 in those at least whose feet are of the ordinary length. 



Tin- apparent number of the caudal segments varies. In both 

 sexes of several it is seven ; in others, however, the males at least, it 

 is less. 



Several of these Crustacea are designated by the vulgar appellation 

 of Araignees de mer or Sea-spiders. 



Although the species of this tribe are very numerous, but two 

 have as yet been discovered except in a fossil state, one of which at 

 least Maia squinado exists at the present day in a living state, and 

 in the same localities f . 



A first division will comprehend those whose second and following 

 feet are similar, and which diminish progressively in size. 



From the latter we will form a first group of all those where the 



tail, either in both sexes, or in the females alone, is composed of seven 



nents. The third joint of the external foot-jaws is almost 



always square, and truncated or notched at the superior internal 



angle. 



large claws, particularly so when compared with the other 

 \\-hieh are extremely short, directed horizontally and perpendi- 

 cularly to the axis of the body, as far as the carpus or joint immedi- 

 ding the hand, then reflected anteriorly on themselves with 

 the linger- ..Ulenly forming an angle ; very short ocular pedi- 



g but little, if at all, from their oavi -tony and 



unexvii or -piny shell, designate the 



PARTHEXOPK, Fab. 

 lateral antennw of some are very short, not exceeding the 



Malar. Brit., 



f Se Desuuur,, Hist. Nat. de Crust. POM. 



