THE CANCKOID CRABS OF AMERICA 149 



absent. Carapace never very broad, but either subcircular, suboval, 

 oblong, or pentagonal. 



KEY TO THE AilJ^RICAN SUBFAMILIES OF THE FAMILY ATELECYCLIDAE 



A'. Movable part of antennae, or that part succeeding the basal article, stout, 



provided with a flagellum. Antennules folding within their cavity. 



• Front, between the antennae, cut into two, three, or four teeth or spines. 



Atelecyclinae, p. 149. 



A-. Movable part of antennae absent or rudimentary. Antennules stout, too 



large to retract within their cavity. Carapace rotund. Front between 



the antennae entire or subentire Acanthocyclinae, p. 170. 



Subfamily Atelecyclinae 



Carapace suboval, oblong or pentagonal. Movable part of antennal 

 peduncle well developed, stout, provided with a flagellum. Anten- 

 nules folding normally within their cavity. Front, between the 

 antennae, cut into two, three, or four spines. 



KEY TO THE AMERICAN GENERA OF THE SUBFAMILY ATELECYCUNAE •' 



A'. Orbits transverse. Lateral margins of carapace well defined by a more or 

 less sharp edge. Legs stout. 

 B'. A triangular projection from the basal antennal article fills the inner 

 hiatus of the orbit. Lateral margins of carapace cut into 6 or 7 large 

 teeth. Surface of body and appendages covered with short bristles which 

 give them the name "horse crabs." Genital openings of female very 

 large, not covered by the appressed abdomen. 

 C^. Carapace pentagonal; lateral teeth 6; frontal denticles 4. Legs 



spinulous Telmessus, p. 150. 



C2. Carapace oblong; lateral teeth 7; frontal teeth 2 in old, sometimes 



4 in young. Legs coarsely spined Erimaorus, p. 155. 



B2. Basal antennal article without a projection filling the orbital hiatus. 

 Lateral margins cut into spines or shallow teeth edged with spinules. 

 C. Carapace oval or oblong-oval and without a long lateral spine; sur- 

 face smooth or granulous Peltarion, p. 160. 



C2. Carapace with long lateral spines. 



D^ Carapace orbicular, smooth except near the margins, and covered 



with a fine velvet, like Dromia-,. Trichopeltarion, p. 167. 



D2. Carapace pentagonal, tuberculate Trachycarcinus, p. 164. 



A". Orbits and eyes pointing forward. Carapace oval; lateral margin not defined 

 except by a few long spines. Legs slender Pliosoma, p. 169. 



NOMEN NUDUM 



Atelecyclus dilatatus Philippi, Zool. Anzeiger, vol. 17, 1894, p, 264; Chile. 



" Milne Edwards (Hist Nat. Crust., vol. 2, 1837, p. 143) makes a species Atelecyclus chitensis, which accord- 

 ing to the description is so closely allied to A. cruentatus Desmarest (in Qufrin, Iconographie du Eegne 

 Anircal, vol. 2, pi. 2, fig. 2-2c) that it is but a variation of it. Milne Edwards gives as a possible synonym 

 the Cancer undecimdentatus of Herbit (Naturg. d. Krabben u. Krebse, vol. 1, r83, p. 181, pi. 10, fig. 60). 

 I am able to conflrni its identity, as there lies before me a photograph of one of Ilerbst's three type-specimens 

 In the Berlin Museum which are labeled "Am. bor."; also a photograph of a female of the same species in 

 the Copenhagen Museum and labeled "ex Ind. or. Daldorf." Both of the photographs agree with Des- 

 marest's figure (loc. cit.); therefore the valid name of the European species is Atelecyclus undecimdentaivs 

 (Herbst, 1783) = ^!. rotundatus (Olivi, 1792, Zool. Adriat., p. 47, pi. 2, fig. 2)= A. cruentatus Desmarest (1825, 

 Consid. G6n6r. Crust., p. 89). The localities Chile, North America, and East Indies should be considered 

 erroneous. 



