108 SEA-SHORE LIFE 



The Orchid Crab, ( Gecavcinus laieralis, Fig. 76 J, is a land crab, 

 and literally swarms over many of the Florida Keys and West In- 

 dies. It is also found at the Bermudas, and on the coast of South 

 America. The shell is about two inches wide and a little less than 

 this in length, with smooth, rounded edges. The central parts of 

 the back are dark purple— almost black, while the sides of the shell 

 and the large claws are rose-red. The walking legs and under parts 

 are dull yellow. This crab spends almost its entire life upon land, 

 the gills being small and enclosed in large chambers wl ich admit 

 air but maintain the cavity moist. The creature lives under damp 

 logs or leaves, or digs barrows fully three feet in depth ; and is 

 often found fully twenty feet above high tide level. 



It is mainly nocturnal, and great numbers of them crawl about 

 during the night seeking all manner of refuse and carrion upon 

 which they feed. In the spring they all visit the ocean to breed, 

 and in midsummer they retire to the depths of their burrows to 

 moult. The crah is a fairly rapid runner and an excellent climber. 

 It is also a pugnacious fighter, being well protected by its very 

 hard shell. 



The Spider Crabs, (Fig. 77 J. These are sluggish, weak-clawed 

 crabs with remarkably long, slender legs. Their bodies are usually 

 flask-shaped with long, tapering snout, and short eye-stalks. 

 Although apparently stupid, these crabs have what is probably the 

 most highly developed nervous system found in the Crustacea, for 

 the ganglia of the body are often united into a single disk-like brain. 



Many of the spider crabs have the habit of placing l^its of sea- 

 weed, hydroids and other marine growths iipon their backs, so that 

 the crab is completely hidden under a veritable marine garden. It 

 has been found that the crab deliberately bites off fragments of 

 weeds, chews them for a time and places the weeds upon its owji 

 back, where they are caught by the saw-edged or hooked-hairs of 

 the crab's back, and probably also anchored by means of adhesive 

 mucous from the cral)'s mouth. The crab always covers itself with 

 the sort of weeds, etc., found in its immediate vicinity, and if 

 removed to another situation, the appearance of which is different, 

 promptly removes the old weeds and replaces them with those which 

 match the new surroundings. 



One of the spider cra,hs( Macrocheira kanipferij is the largest 



