IN TEE COCOS-KEELING ISLANDS. 27 



changed the white calcareous fore-shore into a dark vegetable 

 mould, its occupation seems gone, and it retires in quest of 

 new land to conquer. 



Further landward the soil is tilled and turned up to the sun 

 and rain Ly a species of Oecarcinus, which lives almost entirely 

 in the dry land, visiting the sea only in times of great drought. 

 A still more effective tiller is the great cocoa-nut crab [Birgus 

 latro), one of the largest of shore Crustacea. It is chiefly noc- 

 turnal in its habits, and is not so often seen as the others. It 

 makes in the ground deep tunnels, larger than rabbit burrows, 

 lined for warmth (?) with cocoa-nut fibre. It has a habit of 

 climbing the cocoa-nut palms, but whether to take the air or 

 for temporary lodging is doubtful ; it does not rob the trees, 

 however, as has been charged against it, since it feeds only on 

 fruits that liave fallen. One of its pincer- claws is developed 

 into an organ of extraordinary power, capable, when the creature 

 is enraged, of breaking a cocoa-nut shell or a man's limb. The 

 inner edges of tlie claw are armed with a series of white 

 enamelled denticulations whose resemblance to teeth is 

 singularly close, even to the irregular scarlet line below them 

 which might pass for gums. The Birgus feeds on the nuts 

 almost exclusively, using its great claw to deuude the fruit of 

 the husk surrounding it, and to get at the eye of the nut, whicli 

 it has learned is the only easy gateway to the interior. 



Of the three eye-spots seen at the end of a cocoa-nut only 

 one permits an easy entrance. The Birgus does not waste its 

 energies in denuding the whole nut, and it never denudes the 

 wrong end. Having pierced the proper eye with one of its 

 spindle ambulatory legs, it rotates the nut round it till the 

 orifice is large enough to permit the insertion of its great claw 

 to break up the shell and triturate its contents, whose particles 

 it then carries to its mouth by means of its other and smaller 

 cheliferous foot. 



From this nutritious diet it accumulates beneath its tail 

 a store of fat, which dissolves by heat into a rich yellow oil, of 

 which a large specimen will often yield as much as two pmts. 

 Thickened in the sun, it forms an excellent substitute for 

 butter in all its uses. I discovered it to be a valuable pre- 

 serving lubricant for guns and steel instruments ; and only 

 when a small bottle of it, which I had had for two. years, was 



