OHDER. 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 antennae 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 ajjpears 

 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 



