THE CANCROID CRABS OF AMERICA 557 



Tersely. Basal article of antennae slender and very short, not nearly 

 reaching front; flagellum very long, much longer than major diameter 

 of orbit. Crests of endostome well developed, the expiratory canals 

 closed in below by the foliaceoiis process of the first maxillipeds; ante- 

 rior edge of merus of slender external maxillipeds not notched. 



Chelipeds long, very massive, not very unequal in either sex; the 

 arm usually projects a long way beyond carapace, its anterior edge 

 sharp, crest-like, serrate; the fingers have usually a thin and sharp 

 cutting edge, best marked on the immobile finger. Legs stout, of 

 moderate length. Third to fifth segments of male abdomen fused. 

 (After Alcock.) 



Red Sea, Indo-Pacific region and west American continent and 

 islands from Cape St. Lucas to Galapagos Islands. 



KEY TO THE AMERICAN SPECIES AND SUBSPECIES OF THE GENUS TRAPEZIA 



A'. Carapace widest at middle in full grown. 



BK Front not prominent, lobes shallow. Lateral projection of carapace a 



tooth cymodoce f erruginea, p. 557. 



B-. Front prominent, lobes strongly marked. Lateral projection a spine. 



Carapace covered with small red spots cymodoce maculata, p. 558. 



A'. Carapace not widening from orbits backward. Front finely denticulate. 

 Lateral projection absent or insignificant digitalis, p. 559. 



TRAPEZIA CYMODOCE FERRUGINEA Latreille 



Plate 228, Figures 1 and 2 



Trapezia f erruginea Latreille, Encyc. Meth., Hist. Nat., Entom., vol. 10, 1825, 



p. 695 (type-locality, Red Sea; type not in Paris Mus.). — Alcock, Journ. 



Asiat. Soc. Bengal, vol. 67, 1898, p. 220. 

 f Trapezia cymodoce S. L Smith, Proc. Boston Soc. Nat. Hist., vol. 12, 1869, 



p. 287; Pearl Islands, Bay of Panama. — Faxon, Mem. Mus. Comp. ZooL, 



vol. 18, 1895, p. 22; Acapulco. 

 Grapsillus ferruginetis Rathbun, Bull. U. S. Fish Comm. for 1903, part 3, 1906, 



p. 865. 

 Trapezia cymodoce f err ugi7iea Rathbun, Mem. Mus. Comp. Zool., vol. 35, 1907, 



p. 58. 



Diagnosis. — Antero-lateral margins diverging backward in the full 

 growTi; lateral projection a tooth or not very spiniform. Front not 

 prominent, lobes shallow. 



Description. — Front not very prominent, but advanced beyond the 

 inner supra-orbital angle, and cut into two shallow lobes, each of which 

 has the inner angle dentiform and the outer angle rounded. Tooth 

 at lower inner angle of orbit not very sharp; outer angle acute but 

 scarcely spiniform; lateral epibranchial tooth short and not very spini- 

 form. Upper border of palm subacute; outer surface smooth, bare and 

 polished. 



Typical cymodoce has the front and all the marginal teeth and spines 

 more prominent than in the subspecies Jerruginea, the upper and lower 



