ORDER BRANCHIOPODA. 
357 
to be tubes, filled with a red liquor. Immediately under the 
buckler, or frontal disk, are situated the antennae and the 
mouth. The antennas are two in number, inserted on each 
side of the mandibles, very short, filiform, and consisting of 
two articulations almost equal. The mouth is composed of 
a squared and advanced labrum; of two strong, corneous 
mandibles, bellied inferiorly, compressed and denticulated 
at their extremity, without palpi; of a large ligula, deeply 
emarginated ; and of two pairs of jaws, in the form of leaflets, 
applied one upon the other, the upper of which are spinous 
and ciliated at the internal edge, and the lower almost mem- 
branaceous, are similar to little false feet ; they terminate by a 
slender elongated articulation, and are lengthened externally, 
at their base, into a sort of auricle, supporting an appendage 
with a single articulation, and ciliated, which may be consi- 
dered as a sort of palpus. The ligula presents, according to M. 
Savigny, a ciliated canal, which conducts directly to the 
oesophagus. The feet, the number of which is about one 
hundred and twenty, diminish insensibly in size from the 
second pair ; they are all very much compressed, foliaceous, 
and are composed of three articulations, not comprehending 
the two long filaments of the end of the two anterior ones, nor 
the two leaflets terminating the following, — pieces which 
may be considered as forming, when united, a fourth arti- 
culation, pincer or forceps like, or with two fingers, lengthened 
and connected into sorts of antenniform filaments. On the 
posterior side of the first articulation is inserted a large trian- 
gular, branchial membrane, and the following, or the second, 
supports also, on the same side, a sac, which is ovaliform, vesi- 
cular, and red. The opposite edge of these feet presents four 
triangular and ciliated leaflets, the upper of which is very 
much approximated to the fingers of the forceps, and appears 
to form a third upon the second feet and the following, as far 
as the tenth pair. In proportion as the size of these organs 
