174 CRUSTACEA EUCARIDA— DECAPODA chap. 



grow. It feeds on the pulp of the cocoa-nut, which it extracts 

 by hammering with its heavy chela on the " eye-hole " until room 

 is made for the small chela to enter and extract the pulp. 

 There is not the slightest doubt that the animal often ascends 

 the coGoa-nut trees for the purpose of picking the nuts, a fact 

 illustrated by a fine photograph by Dr. Andrews, exhibited in the 

 Crustacean G-allery in the Natural History Departments of the 

 British Museum. It uses the husk of the nut to line its 

 burrow, and it is said to have the habit of putting its abdomen 

 into the nut-shell for protection and carrying it about with it. 

 Owing to its terrestrial mode of life, the branchial chamber is 

 highly modified, being divided into two portions — a dorsal space, 

 the linincp of which is thrown into vascular ridges and folds for 

 aerial respiration, and a lower portion where the rudimentary 

 branchiae are situated. Although the Eohber-crab lives ordinarily 

 on land, it must be supposed that these branchiae are of some 

 service ; the young are hatched out as ordinary Zoaeas in the 

 sea, and go through a pelagic existence before seeking the 

 land. At the present time the Eobber-crab is confined to the 

 Pacific and the islands of the Indian Ocean, wherever the cocoa- 

 nut grows. It seems, however, that its association with the 

 cocoa-nut is a comparatively modern one. Mr. C. Hedley, of 

 Sydney, who has had great experience of the Pacific Islands, 

 informs me that the cocoa-nut is not, as is usually supposed, a 

 native of these coral islands, but has been introduced, probably 

 from Mexico, by the Polynesian mariners before the discovery of 

 America by Columbus. Before the introduction of the cocoa- 

 nut the Eobber-crab must have fed on some other tree, possibly 

 the Screw I'ine, Pandanus. 



The abdomen is full of oil, and is much prized as a delicacy 

 by the natives, who tell many strange legends about the 

 creature, but the philosopher may well find its structure more 

 strange than fiction, and the consideration of its morphology an 

 intellectual feast. 



The appearance of the thorax and of the thoracic limbs is 

 thoroughly Pagurid ; the structure of the abdomen is highly 

 peculiar. 



From the ventral surface (Fig. 119) we can see at the tip of 

 the tail three snrall calcified plates, which represent the fifth and 

 sixth terga and the telson. Attached to the sixth segment are 



