352 
CLASS CRUSTACEA. 
form of a beak, of which Schoeffer speaks, and which M. Pre- 
vost calls sucker, is not the labrum ; that the four bodies or 
nipples, placed on the sides, and mentioned by the first, 
are not the mandibles, and the two upper jaws; and that the 
pieces considered by the second as barbies, are also not 
maxillary. The first two feet which, according to Schoeffer, 
are composed but of two articulations, the last going into a 
point, might represent the first two jaw-feet of the decapod 
Crustacea, and the two large antenniform feet of apus. The 
principal male sexual organs, or at least those which are re- 
garded as such, consist of two conoid bodies, biarticulate, 
and coming forth only on pressure, situated on the under part 
of the second ring, at which some vessels end, that proceed 
from the first. M. Prevost presumes that the two vulvae of 
the female are at the extremity of the tail, but do not give 
issue to the eggs. This issue (two apertures, according to 
Schoeffer,) is at the second ring, and communicates interiorly 
with the sac enclosing the eggs, and serving as an external 
matrix. But we are not acquainted with any crustaceous 
animal in which the female sexual organs are placed at the 
posterior extremity of the body, and therefore this opinion 
appears to us to possess but slight foundation. 
The observations of Schoeffer on the hairs of the feet of 
these Crustacea demonstrate, that they are so many aerial 
canals, and even the surface of the feet of which they are 
composed, seems to absorb a portion of the air, which is 
attached to it in the form of small bubbles. 
The Cliirocephale diaphane of Benedict Prevost, and which 
appears to us to have great relations with our branchipe des 
marais , if indeed it differ from it at all, has, on issuing from 
the egg, the body divided into two masses, pretty nearly 
equal, and almost globular. The first presents a simple eye, 
two short antennae, two very large oars, ciliated at the end, 
and two feet, rather short and slender, consisting of five arti- 
