NATURAL SCIENCES OP PHILADELPHIA. 373 



It is evidently congeneric with P. crassipes, the type of Pachygrapsus. We 

 ave specimens from Constantinople in the Smithsonian Museum. 



Cyrtograpsus angclatus. 



Cyrtograpsus angulatus Dana, U. S. Exploring Expedition, Crust, i. 352, pi. 

 xii'. f. 6. 

 In our specimens the ambulatory feet are ciliated toward their extremities. 

 " Rio de la Plata," Capt. Page's Expedition. 



Metasesarma trapezium. 



Sesarma trapezium Dana, loc. cit., i. 354, pi. xxii. f. 8. 



An examination of Prof. Dana's original specimens shows that this species 

 belongs to M. Edwards' genus Metasesarma. 



Geothelphusa berardi. 



Thelphusa berardi Savigny, " Egypte " Crust, pi. ii. f. 6. M. Edw., Hist. Nat. 

 des Crust, ii. 14; Mel. Carcin. p. 178. 



We have specimens from Egypt, brought home by Mr. Marsh. 



POTAMOCARCINUS DENTICULATUS, n. Sp. 



The following description will serve to distinguish it from P. armatus the 

 only species hitherto known. 



Carapax flattened, obsoletely granulated. Antei'o-lateral margin denticu- 

 lated ; little teeth about eighteen in number on each side. Meros or fourth 

 joint of the external maxillipeds broad, almost quadrate. Length of carapax 

 in a male, 084 ; breadth 1-22 inch. 



In the river Atrato, New Grenada. Atrato Exploring Expedition. 



DlLOCARCINUS PICTA. 



Dilocarcinus pictus M. Edw., Arch, du Mus. vii. 181, pi. iv. f. 2. 



Paraguay, Capt. Page's Expedition. 



Dr. Randall's genus Orthostomas was founded on a species of M. Edwards' 

 subsequently constituted Dilocarcinu. This name has, however, been used 

 twice previously in Articultata. 



Dilocarcinus pagei, n. sp. 



A species closely allied to Dilocarcinus spinifer M. Edw. It differs, however 

 in the following particulars : The surface of the carapax is more even, the 

 limits of the regions being scarcely traceable. The seven teeth of the antero- 

 lateral margin are arranged as in Dilocarcinus castelnaui M. Edw., the second 

 tooth not being distant from the angle of the orbit. The inferior margin of 

 the orbit is armed with six very sharp, slender spines. The inferior margin 

 of the meros-joint in the chelipeds is four-spined ; while the joint preceding 

 it is one-spined. From D. castelnaui, which it resembles in the shape of the 

 carapax, etc., it differs in having five sharp spines at the anterolateral angle 

 of the buccal area. 



Paraguay, Capt. Page. 



A Monograph of the Genus .EGIOTHUS, with descriptions of new species. 



BY ELLIOTT COUES. 



Since the publication, in 1858, of the Ninth Volume of the Reports on the 

 Pacific Rail Road Surveys the General Report on the Birds the amount of 

 material has steadily and rapidly increased, until there is, at the present day, 

 more than double the number of specimens in the museum of the Smithsonian 



1861.] 



