ALIMA. CRUSTACEA. 171 



E. vitreus, Lat. Shell smooth, carinatecL, with the angles pointed, 

 and a short spine at the posterior part of the back ; toe or nail of 

 the great claws without teeth. 10 lines long. Inhabits Atlan- 

 tic Ocean. Reg. An. iii. 45. 



Gen. 3. A LIMA, Leach. 



Characters as in the preceding genus, but the body and tail ex- 

 tremely elongated, as well as the shell or buckler ; intermediate 

 antennae with a very long peduncle of three cylindrical joints, 

 that at the base longest, terminated by three cylindrical un- 

 equal filaments ; eyes very large ; shell thin, broader behind 

 than before, terminated anteriorly by three points ; first seg- 

 ment without feet ; the second, third, and fourth with very 

 small appendages, and the five following segments furnished 

 each with a pair of oval plates. 



A. hyalina, Leach. Body transparent. 13 lines long ; shell 2 lines 

 broad. Inhabits African seas Desm. Crust. 253. 



FAMILY IT. BIPELTATA. 



Body flattened, membranous and diaphanous ; thorax divided 

 into two shields, of which the anterior is very large, and more 

 or less oval, and the second, supporting the feet-jaws and the 

 five pairs of feet are transverse and angular ; feet, except the 

 last two and the posterior feet-jaws, filiform ; intermediate 

 antennae with two filaments. 



Gen. 4. PHYLLOSOMA, Leach, Lat. 



Antennae in the same horizontal line, the intermediate shorter 

 than the ocular peduncles ; mouth small, below the shell ; six- 

 teen feet, twelve large, and four very small ones near the 

 mouth ; body extremely depressed, like a leaf, and transpa- 

 rent. 



P. clavicorne, Leach. Plate of the head oval and entire ; length of 

 the exterior antennae triple that of the ocular peduncles ; the 

 first pair of exterior feet long. Seas of Africa. Desm. Crust. 255. 



ORDER III. LJEMODIPODA. 



Head not distinct from the first segment of the trunk ; vesicu- 

 lar bodies to the number of four under the second and third 

 segments of the body, and supposed to be respiratory organs ; 

 four setaceous multiarticulate antennae ; mandibles without 

 palpi ; post-abdomen short. 



The eyes in this group are always fixed. The first pair of exterior feet-jaws are 

 placed over the mouth, and form a kind of under lip, and the lower four are used as feet. 

 The body is annulated in all its length, but without a shell ; and the feet are gene- 

 rally unguiculated. They have generally fourteen feet, of which the anterior four 

 are pedipalpous. A valvular sac of four scales situated beneath the feet contains 

 the ova. 



