NATURAL SCIENCES OF PHILADELPHIA. 
373 
It is evidently congeneric with P. crassipes i the type of Pachygrapsus. We 
ave specimens from Constantinople in the Smithsonian Museum. 
Cyrtograpsus angulatus. 
Cyrtograpsus angulatus Dana, U. S. Exploring Expedition, Crust, i. 352, ph 
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. Antero-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, 0-84 ; breadth 1-22 inch. 
In the river Atrato, New Grenada. Atrato Exploring Expedition. 
Dilocarcinus 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 Articultafa. 
Dilocarcinus pagei, n. sp. 
A species clo'sely 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 antero-lateral angle 
of the buccal area. 
Paraguay, Capt. Page. 
A Monograph of the Genus 2EGI0THUS, 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.] 
