428 



A. E. Verrill — Decapod Crustacea of Bermuda. 



The antennules are small, folding vertically, the tips reaching but 

 little beyond the eyes. Antenuse small, about as long as the eve- 

 stalks. Outer maxillipeds have the merus short and broad, with a 

 decided notch on the inner distal edge, at the articulation of palpus. 

 The ischium is broader than long, with a rounded or semicircular 

 lobe on its inner margin ; exognath is small and short. The large 

 palpi occupy about all the space to the bases of the antennules. 

 The anterior lobe of the sternum separates the bases of the max- 

 illipeds. Legs and maxillipeds very hairv. 



The abdomen is convex and has the rings thin, but somewhat 

 indurated above. In the female the edges are expanded and form a 

 well developed egg-pouch below, containing eggs in two specimens. 



Figure 48. — Troglocarcinus corallicola, ? , anterior parts, from below ; diagram- 

 matic sketch, much enlarged, from a Dominica specimen. 



This curious species lives in oven-shaped cavities or dens formed 

 in the upper surface of living corals, especially of Jlussa, Mceandrct, 

 Dichoc'im'a., etc.; as many as 8-12 such cavities are sometimes found 

 in a coral six inches in diameter. The opening of the den is usually 

 semicircular or lunate, commonly oblique to the surface of the coral; 

 the opening being preserved, no doubt, by the friction due to the 

 constant motions of the crab. The downturned, rough, and dii't- 

 covered front of the crab serves as a lid or o])ei"culum, closing the 

 aperture very nicely. The crabs can leave their dens, at least when 

 young, as they often do so when the fresh corals are put aside to dry. 

 The full grown crabs are probably unable to leave their dens.* 



Length of carapace in one of the larger females, T"" ; breadth, 

 4™". This one carries eggs. 



It does not appear to be common at Bermuda. Abundant at 

 Dominica I., in Jlussa and Jlceandra clivosa, from 3-5 fathoms 

 (A. H. v., 1906, Yale Mus.). 



* In the figure pi. xxvili, fig. 8, the crab was intentionally placed in a den too 



large for it, in order to show its form. 



