224 
CRUSTACEA. 
whicli when joined, the animal folding np its feet and tail beneath, 
enclose the l)ody inferiorly, and give it a spheroidal appearance. 4'he 
posterior extremity of the tail has no appendage* * * § . 
Anceus, Risso. — Gnathia, Leach. 
The thorax divided into as many segments as there are pairs of 
feet, hnt all the latter simple and monodactyle; four setaceous an- 
tennae; a stout square head with two large projections in tlie form of 
mandibles; extremity of the tail furnished with foliaceous fin-like 
ajjpendages f . 
J^RANizA, Leach. 
Four setaceous antennae, as in the preceding; hut the thorax viewed 
from above ])resents 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 tlie posterior extremity of the body is also pro- 
vided with a fin 
A^arious genera of Messrs. Savigny, Rafinesque and Say§, but the 
characters of which have not been described or sufficiently developed, 
appear to belong to this order of the Amphipoda. Even some of the 
snbgenera T have just quoted require to he 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. 
LA3MODIPODA. 
'rhe Loemodipoda are the only Malacostraca with sessile eyes, in 
which the posterior extremity of the body exhibits no distinct bran- 
chiee, and which arc almost deprived of a tail, the two last feet being 
inserted in that extremity, or the segment which connects them with 
it being merely followed by one 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. 
* Ttiphis oroides, Kisso, Crust., II, 9 ; Desmar., Consul., p. 281, XLVI, 5. 
"t* Anceus forJiciduHs ; Kisso, Crust., II, lO; Dcsuiar., Consid., XLYI, f > ; — A/i- 
ceiis maxillaris ; (inarer Montag., Trans. Lin. Soc., Yll, vi, 2; Desmar. 
Ib., XLYI, 7. 
J Oniscus roerideulus, ISIontag., Trans. Lin. Soc., XI, iv, 2; Encyclop. Method., 
Atl. d’Hist. Nat., CCCXXIX, 28, and CiCCXXIX, 24, 25; Desmar., Consid., 
XLYI, 8. 
§ I can say nothin? of the (V. eryine, Kisso : 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. 
