170 CRUSTACEA. 



Trapezia, Lat. 



The Trapezige resemble the Eriphiae in the insertion of their lateral 

 antennae, but their shell is nearly square, depressed, and smooth ; the 

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

 with the other feet, very large. 



All the species are exotic *, and inhabit Eastern Seas. The 



PiLUMNus, Leach, 



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

 lateral antennae 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, and 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 f. 



Thelphusa, Lat. % 



The lateral atennae 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 

 almost shaped like a truncated heart, and the tarsi are furnished with 

 spinous or dentated ridges. 



Several species are known, all of which inhabit fresh water, 

 but capable, as it would appear, of living at a distance from it 

 for a considerable time. One of them, mentioned by the an 

 cients, is found in the south of Europe, the Levant, and in 

 Egypt; it is the Crabe Jluviafile, oi Belon, Rondelet, and Ges- 

 ner §. It is very common in several brooks and various lakes 

 of the craters of the south of Italy ; its effigy is observable on 

 different antique Grecian medals, particularly on those of Sicily. 

 The shell is about two inches in each diameter. It is greyish or 

 yellowish, as the animal is living or dead, mostly smooth, with 

 little incised rugae and asperities on the anterior sides. The 

 front is transversal, inclined, reflected, and edentated. The 

 claws are rough, with a reddish spot at the extremity of the 

 fingers, which are long, conical, and unequally dentated. The 

 Greek monks eat it raw, and during Lent it forms one of the 

 articles of diet used by the Italians. 



* Cancer cymodoce, Herbst., li, 5 ; — C. rufo-punctatus, Id., xlvii, 6 ; — C. glaher- 

 rimus, Id., xx, 115. See the article Trapi:zie, Encyc. Methodique. 



t Seethe article Pi7Km>ie, Encyc. Method., and Desmarest, op. cit. p. 111. 



X The Pofamophiles of the first edition of this work. That name having been 

 already applied 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 PofamobuF, Leach, Potamon, Savigny. 



§ See Olivier Voy., en Egyptc, pi. xxx, 2 ; and the plates of Nat. Hist., in the 

 great work on that country. 



