153 CRUSTACEA. 



The last subgenus of this subdivision, that of 



Anthosoma, Leach, 



Approximates to Dinemoura in the presence of a siphon, and in 

 the two caudal threads; but it is removed from it, as well as the 

 preceding- ones by its projecting antennae which resemble little mo- 

 nodactyle claws, and by its six last feet which are membranous, 

 united inferiorly, and folded laterally over the post-abdomen, en- 

 veloping it like a case; those of the first and third pairs are ungui- 

 culated; the second feet are terminated by two short and obtuse 

 toes(2). 



There, the body is oval, without salient caudiform appendages, 

 composed of threads or fin-like productions at its posterior extre- 

 mity. A portion of the superior teguments forms a shield, which 

 does not cover its anterior half, is rounded and emarginated before, 

 widened and as if bilobate behind; then follow three pieces or scales, 

 posteriorly rounded and emarginated, the second of which, and the 

 smallest of the three, is almost in the form of a reversed heart; the 

 last, and the largest, is arched. The four posterior feet are in the 

 form of laminae, and are united by pairs; those of the first and the 

 third are unguiculated; the extremity of the second is bifid. The 

 siphon is apparent. The ova are covered by two large, oval, conti- 

 guous, coriaceous pieces, placed under the abdomen, and surpassing 

 it in length. Such are the characters of the genus 



Cecrops, Leach, 



Of which a single species only is known. 



Cecrops Latreillii, Leach, Encyc. Brit.,Supp. I, xx; 1, 3, the 

 male; 2, 4, the female; 5, the antennae magnified; Desmar., Con- 

 sid. L, 2. Found on the branchiae of the Tunny and Turbot. 



The second tribe, that of the Lerneiformes, Lat., consists 

 of Entomostraca, which approximate to the Lerneae, in their 

 external configuration, still more than the preceding subge- 

 nera. There are but ten feet visible(3), mostly very short, 

 and but slightly or nowise adapted to natation. Sometimes 

 the body is nearly vermiform and cylindrical, the anterior 



{2) Anthosoma Smithii, Leach; Desmar., Consid., L, 3; Caligus imbricatus, 

 R'lsso. 



(3)' There are probably two more, as in the preceding subgenera, but they are 

 either indistinct or have such a peculiar form that they have not been recognized. 



