LIFE HISTORY OF THE BLUE CRAB. 399 



c. IMovable portion of the antenna excluded from the orbital cavity by a ^iro- 



longation of the basal joint of the antenna CharyhdcUa. 



c^. Movable portion of the antenna not excluded from the orbit. 



d. No longitudinal ridge on the palate Arenxus. 



d^. A longitudinal ridge on the palate. 



e. Abdomen of the male i-shaped Calllnecles. 



e^ Abdomen of the male triangular Porlnnus. 



b^. Carapace not very broad, antero-lateral margins cut into five teeth. 



c. Last tooth of antero-lateral margin developed into a spine longer than the 



other teeth or spines Bathynectes. 



c\ All antero-lateral teeth similar Ovalipes. 



ci^. Last pair of legs narrow, with terminal segment lanceolate Carcinides. 



Of the nine species of the g'enus CaJUnectes five have been recorded 

 from the United States. The}^ are C. sapidus Rathbun, C ornatus 

 Ordwa}^ C. danx Smith, C. larvatusOYdwRY, and C. exasjjerat us Ordway. 

 Of these the first is distributed along the Atlantic coast from Massa- 

 chusetts Bay to Florida and along the coast of the Gulf of Mexico, 

 the Caribbean Sea, and the Atlantic coast of South America as far 

 south as Brazil; O. ornatus Ordway has been found as far north as 

 Charleston, S. C, and thence southward to Victoria, Brazil; C. dand& 

 Smith has been collected at various localities between South Carolina 

 and Santos, Brazil" ; C. larvatus Ordwa}" has been reported from some 

 of the Florida ke3^s, from Vera Cruz, Mexico, from various islands of 

 the Bahamas and the West Indies, from the coast of Brazil, and from 

 the West coast of Africa; C. exasperatns Ordwa}' has been collected at 

 Key West., Fla., Jamaica, Old Providence, and at several points on 

 the coast of Brazil. In addition to these, C. hocourti Mihie-Edwards 

 occurs on the coasts of Central and South America; C. arcuatus Ord- 

 way is found in the Gulf of California and Pacific coasts of Mexico 

 and Central America; C. toxotes Ordwaj^ from Cape St. Lucas to Guaya- 

 c^iil, Ecuador; C. helUcosvs (Stimpson) from numerous points in Lower 

 California and in the Gulf of California; and C. nitidus A. ]\iilne 

 Edwards from Guatemala prolmbl}^ to Chile. 



Some of the species are very distinct, but others are distinguished 

 with difficulty. The following key, revised from Miss Rathbun's, will 

 serve for their identification. 



«. Inner supraorbital fissure closed. 



h. Front Avith four intraorbital teeth C. scqndus. 



¥. Front Avith six intraorbital teeth. 



c. Verges much shorter than the abdomen. 



d. Lateral spine more than twice the length of preceding tooth. 

 €. Intramedial region broad, its anterior width about three times its 

 length C. ornatus. 



« The occurrence of C. sapklus in a fresh water basin at Rochefort, France, recorded 

 by Bouvier (Bulletin Musee Paris, VII, 16), is, as that author suggests, to be regarded 

 as entirely accidental, the specimen having been carried across the Atlantic in some 

 vessel. 



