96 CRUSTACEA. 



Praniza, Leach. 



Four setaceous antennae, as in the preceding; but the thorax viewed 

 from above presents but three segments, the two first of 'which are 

 very short and transverse, each supporting a pair of feet, while the 

 third, much larger and longitudinal, supports the others. The feet 

 are simple; the head is triangular, pointed before, and has prominent 

 eyes. Each side of the posterior extremity of the body is also pro- 

 vided with a fin(l). 



Various genera of Messrs Savigny, Rafinesque and Say(2), but 

 the characters of which have not been described or sufficiently de- 

 veloped, appear to belong to this order of the Amphipoda. Even 

 some of the subgenera I have just quoted, require to be re-examined. 



M. Milne Edwards has made several valuable and detailed obser- 

 vations on several of these Crustacea, which will most certainly tend 

 to elucidate the subject. 



ORDER IV. 

 LiEMODIPODA. 



The Laemodipoda are the only Malacostraca with sessile 

 eyes, in which the posterior extremity of the body exhibits 

 no distinct branchiae, and which are almost deprived of a tail, 

 the two last feet being inserted in that extremity, or the seg- 

 ment which connects them with it being merely followed by 

 one or two very small joints. They are also the only ones in 

 which the two anterior feet, that correspond to the second 

 foot-jaws, form part of the head. 



They all have four setaceous antennse supported by a triar- 



(1) Oniscus ccerukatus, Montag., Trans. Lin. Soc, XI, iv, 2; Encyclop. Method., 

 Atl. d'Hist. Nat., CCCXXIX, 28, and CCCXXIX, 24, 25; Desmar. Consid., 

 XLVI, 8. 



(2) I can say nothing' of the G. ergine, l^isso: the number of its feet would seem 

 to place it in the last section of the Amphipoda; while the manner in which they 

 terminate, and the number of the segments of the body, appear to throw it among- 

 the Isopoda. 



