g2 BULLETIN 16G, UNITED STATES NATIONAL MUSEUM 



and palate distinct, vault of palate shallow. External maxillipeds 

 pediform or suboperculiform. Chelipeds and legs long and slender. 

 Only the last pair of legs is dorsal and reduced in size. Sternum of 

 female broad. Abdomen of male and usually of female, consists of 

 seven separate segments. Gills phyllobranchiate; gill-plumes vary 

 from 14 to 8 on either side. (After Alcock.) 



KEY TO THE FAMILIES OF THE THELXIOPEIDEA 



A'. Gills 13 or 14 on eacli side. Mastigobranchs on first one or 

 three pairs of legs. First article of ej^estalks not much 

 longer than second Thelxiopeidae (p. 62) 



A^. Gills 8 on each side. Mastigobranchs not found on any legs. 



First article of eyestalks much longer than second Latreilliidae (p. 63) 



Family THELXIOPEIDAE, new name 



Homolidae Henderson, Voyage of H. M. S. Challenger, vol. 27, Anomura, p. 18, 

 1888. — Ortmann in Bronn's lOassen und Ordnungen des Thier-Reichs, vol. 

 5, pt. 2, Arthropoda, p. 1155, 1901. 



Carapace elongate-quadrangular, ovoid or urn-shaped. Terminal 

 joint of eyestalk, including eye, either longer or shorter than the 

 slender basal joint. Antennal flagella much longer than carapace. 

 External maxillipeds pediform or subpediform. 



KET TO THE AMERICAN GENERA OP THE FAMILY THELXIOPEIDAE 



A^ Carapace broadest anteriorly. Second article of antennal 



peduncle with antero-external spine Thelxiope (p. 62) 



A*. Carapace broadest posteriorly. Second article of antennal 

 peduncle without antero-external spine. 



B'. Carapace with dorsolateral margins. Rostrum short Paromola (p. 68) 



B2. Carapace without dorsolateral margins. Rostrum elon- 

 gate Homologenus (p. 70) 



Genus THELXIOPE Rafinesque 



Hippocarcinus Aldrovandi, De moUibus, crustaceis, testaceis et zoophytis, 



p. 178, 1606 (type, H. hispidus Aldrovandi). 

 Thelxiope Rafinesque, Precis des decouvertes et travaux somiologiques, p. 21, 



1814 (type, T. palpigera Rafinesque). 

 Honiola Leach, Trans. Linn. Soc. London, vol. 11, p. 324, 1815 (type, H. spini- 



frons Lamarck); Zoological miscellany, vol. 2, p. 82, 1815. — Alcock, Journ. 



Asiat. Soc. Bengal, vol. 68, p. 154 and synonymy, 1899. 

 Homolus Leach, in Diet. Sci. Nat., vol. 21, p. 416, 1821. Leach here recognizes 



that Rafinesque and Latreille had described the same genus under the names 



Thelaiope [Thelxiope] and Hippocarcin. [Hippocarcinus], respectively. 



Carapace square-cut, longer than broad, broadest in front, and 

 with deep vertical sides; gastric region well demarcated and occupy- 

 ing the anterior half of carapace, linea anomurica distinct and dorsal. 

 Front narrow, forming a rostrum, either entire or bifid at tip, and 

 with a spine on either side of its base. Orbits quite incomplete, not 

 concealing eyestalks, and the eyes, which project far outside them, 



