90 Bulletin, Vanderlilt Marine Museum, Vol. II 



Material examined: One female, trapped in lobster pot, Miami, 

 Florida, in the Bay of Biscayne ; one very large male, dredged on the 

 Florida Reefs, 1923, by the *'Ara." One young female, scarcely one- 

 half inch wide but heavily egg-laden, dredged in 7 fms.. Bury Island, 

 Bahamas, January 19, 1925, 



Color: The "coral" crab takes its name, not from the fact that 

 it is an inhabitant of the coral reefs, but from the exquisite coloration 

 and sculpturing of its body, which recall the red coral so highly prized 

 by the ancients and used even today as a jewel. The carapace and 

 ambulatories of the crab are coral red with brighter bands of red at 

 the distal joints, ends of the joints and flecks of pale yellow on the 

 upper surface. The chelipeds are likewise brighter, especially in the 

 male specimens. The underparts of the body are bluish. The eyes 

 are black, beadlike. 



Habits : Mithrax hispidus is chiefly nocturnal, spending the greater 

 part of the daytime quiescent among the coral rocks which it so closely 

 resembles in contour and coloration. It is both carnivorous and herb- 

 ivorous, feeding on the smaller fishes, crustaceans, worms, etc., and 

 the tender shoots of turtle-grass, sea-lettuce and similar marine plants. 

 For notes of the rate of growth see my report on the * ' Crustacea from 

 Tropical East American Seas," p. 38, 



Technical description: Carapace tumid, one-sixth wider than 

 long, devoid of branchial sulci, smooth except for a few, low, rounded 

 tubercles on the outer branchial region; cervical and urogastric 

 grooves deep ; cardiac groove deep in young specimens, shallower in 

 older ones ; gastric tubercles well defined in young, nearly obsolete in 

 older specimens. Rostral horns blunt, short, separated by a U-shaped 

 sinus, subequal to either horn. The orbit is surrounded by four 

 unequal spines besides the antennal; of these four, the inner and 

 outer are subequal, obtuse, the others are smaller, more rounded. The 

 larger antennal spine, which slightly exceeds the rostrals in length, is 

 subacute, with tips incurved ; the outer, smaller antennal spine is sub- 

 equal to the inner orbital, and has a small tubercle at its base. There 

 are five spines on the lateral margin, the first is hepatic, obtuse, occa- 

 sionally bifid, the second spine is decidedly bifid, its posterior point 

 being the longer and forward curved, the third and fourth teeth are 

 longer, slenderer than the second with the tip decidedly curved for- 

 ward; the fifth tooth is much smaller, postlateral and placed higher 

 upon the carapace. There are two tubercles on the subhepatic region 



