38 NEW-YOKK FAUNA — CRUSTACEA. 



Genus Amphithoe, Leach. General characters of the preceding;. No setaceous appendix to the third 

 joint of the upper antenna;. Tail without fasciculated spines, armed with bifid spines at the 

 tip. Hands of the two anterior pair oval. Inhabiting fresh and salt water. 

 A. serrata. (Say, 1. c. p. 383.) Antenna? equal, short, stout; eyes large, approximated, suboval; 



eighth, ninth and tenth segments of the body serrated ; three spines on the lower edge of the palm. 



Length, 0*4. Egg harbor, New-Jersey. 

 A. dentata. (Id. lb) Posterior edge of the dilated thighs strongly serrated; eyes distant abore; 



clypeus obtuse; hand truncate at tip, destitute of prominent teeth, but with a few rigid hairs. 



Length, 0'3. Fresh water marshes. South-Carolina. 

 A. punctata. (Id. lb.) Lower antennae nearly as long as the body; hands oval, not dentated nor 



larger than the carpus. Body and antenna? sprinkled with black poit.ts. Length, 0-35. Egg 



harbor, New-Jersey. 



Genus Cerapus, Say. Antenna; very large and robust, nearly equal; the upper of four joints, the 

 lower or lateral ones of five. Anterior pair of feet small, monodactyle; the second pair with 

 a broad palm and a two-jointed thumb. Head distinct, ending in a small rostrum. 

 C. tubularis. (Id. p. 49. C. abditus, Templeton, Tr. Ent. Soc. Lond. Vol. 1, pi. 20, fig. 5. See 

 Pl. 10, fig. 43 o~ this work.) Head with a mucronate carina before; hand and first joint of the 

 thumb with one or two obtuse teeth ; eyes oval, black. Color. Body above blackish, with irregu- 

 lar paler spots; antenna; and feet white; joints tipped with blackish: two hind pair of feet and tail 

 white. Inhabiting a membranous tube open at both ends. Length, 0-25. Sea-beach, Egg 

 harbor, New-Jersey. 



Genus LEPrDACTYLis, Say. Upper antenna? with a setaceous appendix at the tip of the third joint 



Head produced into a point. Body compressed, oval. Feet fourteen. Two anterior pair of 



feet simple, equal ; third and fourth subequal, didactyle, fingers lamelliform ; the remaining 



pairs spinous, without nails. 



L. dytiscus. (Say, I.e. p. 380.) Eyes orbicular; setaceous appendix reaching the tip of the fourth 



segment of the terminal joint; anterior pairs of feet hairy. Color: Body, when recent, white, 



with a ferruginous short stripe within. Length, • 15 - -25. Coast of Georgia. 



Genus Uxciola, Say. Upper antennae robust, subpediform, with an articulated seta at the base of the 

 fourth join*. Feet fourteen, of which the first pair are monodactyle, the second with adactyle 

 compressed hands with two minute hooks at the tip ; coxa; simple, not dilated. Allied to 

 Podocerus. 

 U. irrora'a. (Id. lb. p. 389.) Eyes conspicuous, rounded. Hands of the anterior feet with a longi- 

 tudinal palm and prominent tocth ; those of the second pair compressed, ciliated, with a subtriangu- 

 lar hand. Color, when recent, pale with numerous red points. Length, 0'3. Hab. seaweed on 

 the coast of New-Jersey. 



