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U.S. NATIONAL MUSEUM BULLETIN 292 



pale lavender below; both fingers white except for bluish lavender on 

 upper proximal portion of dactyl. Basal segments of walking legs gray 

 to brown with dark brown longitudinal stripes and variable pattern 

 of light spots. 



Material examined. — The Dominican collections contain 13 

 males (carapace lengths 8.5-32.0 mm), 14 females (cl 8.8-28.1 mm), 

 and 12 juveniles (cl 5.0-9.3 mm). In the smallest identifiable male, 

 the pleopods are very short and vestigial, but no pleopods were 

 detectable in one slightly larger specimen. Egg membranes were still 

 attached to the pleopods of the largest female, collected in March. 



Ecological notes. — Neither the habits nor habitat of Ocypode 

 quadrata on Dominica differ from those observed elsewhere in its 

 range. The members of this species seem to be confined to sandy 



Figure 69. — Denuded terminal portion of right first pleopod of male Ocypode quadrata 

 shown in figure 68: a, posterior view; b, lateral view; c, anterior view. 



beaches, where they construct burrows of two types. One is vertical 

 or slightly sloping downward to depths of two feet, and the other is 

 U-shaped. In some of the latter, apparently unfinished ones, one of 

 the arms of the U does not reach the surface, and even in those that 

 do, the opening is so small that the crab cannot emerge through it 

 without enlarging it. This is accomplished quickly, for a number of 

 animals escaped capture when they retreated through the secondary 

 aperture while the collector was digging toward them through the 

 primary opening. 



On a few occasions when a crab wandered some distance from its 

 burrow and was blocked from returning to it, the crab sought refuge 

 in the burrow of another crab. This invasion of another individual's 

 burrow, however, probably was a measure of last resort, for all of 

 those individuals that were pursued made every effort to get back to 

 their own buiTows. 



