10 BULLETIN 152, UNITED STATES NATIONAL MUSEUM 



F-. Sides of the body strongly arched. Shape transversely 

 oval. Front narrower. Land-crabs. 



Famil}' Gecarcinidae. 

 W. The third maxillipeds almost or quite close the mouth. 

 Front moderately or very narrow. 



Family Ocypodidae. 

 B^. Merus of third maxillipeds small, bearing terminally a carpus of nearly 

 its own width. Ischium very broad. Body somewhat oblong. First 

 antennae not retractile into sockets. Parasitic on corals. 



Family Hapalocarcinidae. 



Superfamily BRACHYRHYNCHA 



The fore part of the body is broad, the rostrum reduced or alto- 

 gether wantmg. The body is oval, round, or square, usually broader 

 than long. The orbits are nearly always well enclosed. 



Family EURYALIDAE ' (CORYSTIDAE restricted ') 



Corystiens (part) Milne Edwards, Hist. Nat. Crust., vol. 2, 1837, p. 139. 

 Corystoidea — Corystidae (part) Dana, U. S. Expl. Exped., vol. 13, Crust., pt. 1, 



1852, pp. 296 and 297. 

 Corystoidea (part) Miers, Challenger Rept., ZooL, vol. 17, 1886, p. 209. 

 Majoidea corystoidea (part) Ortmann, Zool. Jahrb., Syst., vol. 7, 1893, pp. 26 



and 28. 

 Oxyrhyncha — Corystidae (part) Ortmann, in Bronn's Thier-Reich, vol. 5, pt. 2, 



1898, p. 1166. 

 Corystidae (part) Alcock, Journ. Asiat. Soc. Bengal, vol. 68, 1899, p. 103. 



Carapace longer than broad, suboval, convex from side to side, 

 regions not well defined. Front rather prominent, cut into three 

 (in American species) or two teeth. Antennules normal, small, 

 folding longitudinally. Antennae long, unusually coarse and seta- 

 ceous. There is no epistome and the external maxillipeds, which are 

 elongate and sometimes have a slight pediform cast, extend almost up 

 to the antennules. Buccal orifice elongate and square cut with the 

 anterior angles rounded and slightly convergent. 



KEY TO THE AMERICAN GENERA OF THE FAMILY EURYALIDAE 



A^ Legs gressorial. Lateral teeth of carapace both before and behind the middle. 



Size small, not over 10 mm. in length Gomeza, p. 10. 



A^. Legs somewhat natatory. Lateral teeth of carapace before the middle 



only. Size large, over 50 mm. in length Pseudocorystes, p. 11. 



Genus GOMEZA Gray 



Gomeza Gray, Zool. Misc., 1831, p. 39; type, G. bicornis Gray. 

 Oeidea db Haan, Fauna Japon., Crust., 1833, pp. 4 and 15; type, 0. vigintispinosa 

 DE Haan. 



Carapace elongate, subelliptical, sides dentate behind as well as in 

 front of middle, rostrum triangulate. Eyes small or medium. Merus 



* Euryala Weber, 1793 takes precedence of Corystes Latreille 1802, both having the same type; hence 

 Euryalidae instead of Corystidae. See Rathbun, Proc. Biol. Soc. Washington, vol. 17, 1904, p. 171. 

 » For the genera Bellia and Corystoides, see under Family Atelecyclidae, subfamily Acanthocyclinae. 



