THE SPIDER CRABS OF AMERICA 



345 



Genus HEMUS A. Milne Edwards 



Hemus A. Milne Edwards, Crust. Reg. Mex., 1895, p. 88; type, H. cristu- 

 lipes A. Milne Edwards. — Rathbun, Bull. U. S. Fish Comm., vol. 20, for 

 1900, pt. 2, 1901, p. 62. « 



Carapace thick and swollen; longer than wide. Rostrum small; 

 no preorbital spines; orbit incomplete below. First and second 

 movable articles of the external antennae 

 remarkably wide and flat; the miiltiarticu- 

 late flagellum inserted at the external angle 

 of the second. Merus of outer maxillipeds 

 long and little dilated outwards; exognath 

 very wide in its basal and middle portion, 

 narrowing toward its extremity. Chelipeds 

 small; fingers slightly gaping, strongly bent 

 inward toward their extremity", but scarcely 

 spoon-shaped. Ambulatory legs short, but 

 very strong; merus ornamented with cristi- 

 form prolongations; dactyli strong, much 

 curved, without denticulations below. 



The dilated legs fit together in such a way 

 that with the antennal peduncle and the 

 deflexed rostrum, they form a large cavity 

 underneath the body. 



Contains only the two following allied species occurring on opposite 

 shores of the continent: cristvlipes (Atlantic), analogus (Pacific). 



Fig. 110.— Hemus cristulipes 

 (19724), MAXILLIPED, X 30.7 



KEY TO THE SPECIES OF THE GENUS HEMUS 



A '. Tips of rostrum separated by a sinus wider than either tip. Cardiac promi- 

 nence high cristulipes, p. 345. 



A ^. Tips of rostrum almost contiguous. Cardiac prominence larger, embracing 

 part of the branchial regions and of the intestinal region, .analogus, p. 347. 



HEMUS CRISTULIPES A. MUne Edwards 



Plate 124, fig. 1; plate 248, figs. 9-15 



Hemus cristulipes A. Milne Edwards, Crust. Reg. Mex., 1875, p. 88, pi. 16, 

 figs. 1-1/ (type-locality, near Contoy, at the entrance of the Gulf of 

 Mexico, 12 to 18 fathoms; holotype. Cat. No. 1943, M. C. Z.). — Auri- 

 viLLius, K. Sv. Vet.-Akad. Hand., vol. 23, pt. 1, 1889, p. 45, pi. 3, fig. 6. — 

 Rathbun, Bull. U. S. Fish Comm., vol. 20, for 1900, pt. 2, 1901, p. 63. 



Diagnosis. — Tips of rostrum separated b}^ a sinus wider than either 

 tip. Cardiac region prominent. Margins of merus joints of legs 

 faintly crenulate. 



Description. — Body and legs covered with depressed granules. The 

 rostrum is wide, short, bicarinated above, bent downward, and bifur- 

 cated at its extremity. Upper orbital border unarmed, but having a 

 narrow fissure; the postorbital cavity into which the eye can be 



