PROTECTIVE coloration and habits have interested most biologists. Few of the very many articles on these topics mention a remarkable example among the crustaceans. Certainly the ghost crab is large enough to be noticed easily, and is common from Atlantic City to Rio de Janeiro, on beaches where people vacation every summer and should have time for interesting observations. Yet there is only one good scientific report on the ghost crab of our Atlantic coastline, and this comes not from the American mainland but from the iiow abandoned laboratory of the Carnegie Institution of Washington on Loggerhead Key in the Dry Tortugas, beyond the tip of Florida. It would seem that the ghost crab has succeeded in concealing itself f rom zoologists as well as the general public. The first observations made on this ghost crab were by the French naturalist, L. A. G. Bosc, on the coast of "Carolina" prior to 1802. Although Bosc grouped the fiddler crab (Uca pugilator (Latr.)) with the ghost crab '(Ocypoda quadrata (Fab.)) in the genus Ocypode (the latter as 0. albicans Bosc), his account shows clearly that he watched both of these land forms in the living state. Concerning the ghost crab, Bosc noted that "when they fear some danger, they save themselves by walking sidewise into their burrow with such rapidity that this naturalist was a long time observing them before forming an idea about the species of animal which was fleeing before him; it finally took all the speed of his horse to procure several specimens of them, again after several futile attempts. One knows well that an animal which is so difficult to catch can not serve commonly as nourishment; thus in Carolina no one makes any use of them. These