30 CRUSTACEA. 



Eriphia, Lat. 



Where the lateral antennae are inserted between the ocular cavi- 

 ties and the median antennae: the nearly cordiform shell is truncated 

 posteriorly, and the eyes are removed from its anterior angles. 



The coast of France furnishes a species — Cancer spinifrons, 

 Fab.; Herbst., XI, 65; Desmar., Consider., XIV, 1, which 

 is the Pagicrus of Aldrovandus. The sides of its shell are fur- 

 nished with five teeth, the second and third bifid. The front 

 and claws are spiny; the fingers black. 



Trapezia, Lat. 



The TrapezicC resemble the Eriphise in the insertion of their late- 

 ral antennse, but their shell is nearly square, depressed, and smooth; 

 the eyes are placed at its anterior angles, and the claws, in compa- 

 rison with the other feet, very large. 



All the species are cxotic(l), and inhabit Eastern Seas. The 



PiLUMNus, Leach, 



Differs from the two preceding subgenera, in the insertion of the 

 lateral antenna; at the internal extremity of the ocular cavities, 

 above the origin of the pedicles of the eyes. The Pilumni, as to the 

 form of the shell, approach nearer to the Crustacea of the second 

 section, than the other Quadrilatera, atid in this respect stand some- 

 what ambiguously between the two. As in most of the Arcuata the 

 third joint of their foot-jaw is nearly square or pentagonal. The 

 lateral antennae are longer than the ocular pedicles, and have a seta- 

 ceous stem longer than the peduncle and composed of numerous 

 small joints. The tarsi are simply pilose(2). 



Thelphusa, Lat.(3) 



The lateral antennae situated as in the Pilumni, but shorter than 

 the ocular pedicles, composed of but few joints, and with a cylin- 

 drico-conical stem hardly longer than its peduncle. The shell is 



(1) Cancer cymodoce, Herbst., li, 5;~C. rufo-pundaius. Id., xlvii, 6;—C. glaber- 

 rimus. Id., xx, 115. See the article Trap^zie, Encyc. Methodique. 



(2) Seethe article Pj7«??ine, Encyc. Method., and Desmarest, op.cit. p. 111. 



(3) The Potamophiles of the first edition of this work. That name having- been 

 already apphed to a genus of Coleopterous Insects, I have substituted the present 

 one.— See this word in the second edition of the Nouv. Diet. d'Hist. Nat. They 

 are the Potamobise, Leach, Potamon, Savigny. 



