LONG-TAILED GROUP 



3231 



manner that its mouth and tentacles are situated immediately below the fore part of 

 the crab's body. It is thus able to share in the meals that the crab procures for 

 itself, and the companionship is consequently mutually beneficial to the two. An 

 advantage conferred upon the crab by the presence of the anemone results from the 

 fact that the latter gradually absorbs the shell in which the former is lodged, so 

 that there is no occasion for it to change its abode with growth, the soft tissues of 

 the polyp offering no resistance to the crab's increase in size. Certain hermit crabs 

 have forsaken the sea as a permanent abode, and spend the greater part of their 

 lives on land. For instance, the 

 genus Cenobita, which occurs both 

 in the West Indies and India, may 

 be met with in forests far from the 

 coast. The best known of these ter- 

 restrial forms is the great cocoanut 

 crab (Birgus latro), found in the 

 islands of the Indo-Pacific seas, 

 and remarkable not only for its 

 great size and habits, but also for 

 having the abdomen symmetrical 

 and covered above with a series of 

 horny plates. These animals in- 

 habit deep burrows, which they hol- 

 low out beneath the roots of trees, 

 and carpet with fibres stripped from 

 cocoanuts. Periodically, however, 

 they are compelled to visit the sea 

 to moisten their gills; and here 

 they lay their eggs, the young being 

 hatched and living for some time on 

 the coast. They live principally 

 upon cocoanuts, which fall from the 

 palms, but they do not climb the 

 trees after the fruit. To get at 

 the contents of the nut, the crab 

 first tears away the fibre overlying 

 the three ' ' eyes, ' ' and then ham- 

 mers away with its claws at the latter 

 until a hole is made, when it extracts 

 the kernel by means of its smaller 

 pincers. Some observers state that 

 after drilling through the perforated 

 eye, the crab grasps the nut in its 

 claws and breaks it against a stone. 

 In the next tribe, or Thalas- 

 sinidea, the carapace is much com- 



ONE-CI.AWED LOBSTER, Thaumastocheles zeleuca. 

 (Natural size.) 



