478 
THE OCEAN WORLD. 
leagues coyeared with these heaps. They dilute the mud, which is 
carried out by the ebbing tide, and the surface of the bay is left 
smooth, as it was in the preceding autumn. 
We hare said that the Crustaceans do not even respect each other ; 
the larger of the same species often devour the smaller, j Bara con- 
cordia fratrum! Mr. Eymer Jones relates that he had on one 
occasion introduced six crabs ( Platycarcinua par/nr us) of different size 
into an aquarium. One of them, venturing towards the middle of the 
reservoir, was immediately accosted by another a little larger, which 
took it with its claws as it might have taken a biscuit, and set about 
breaking its shell, and so found a way to its flesh. It dug its crooked 
claws into it with voluptuous enjoyment, appearing to pay no attention 
to the anger and jealousy of another of its companions, which was still 
stronger and as cruel, and advanced towards them. But, as Horace 
says— and he was not the first to say it — “ No one is altogether happy 
in this lower world 
“ Nihil est ab omni parte beatum.” 
Our ferocious Crustacean quietly continued its repast, when its com- 
panion seized it exactly as it had seized its prey, broke and tore it in 
the same fashion, penetrating to its middle, and tearing out its 
entrails in the same savage manner. In the meantime tho victim, 
singularly enough, did not disturb itself for an instant, but continued 
to eat the first crab bit by bit, until it was itself entirely torn to pieces 
by its own executioner — a remarkable instance at once of insensi- 
bility to pain and of cruel infliction under the lex ialionis. To eat 
and to be eaten seems to be one of the great laws of Nature. 
Though essentially carnivorous, the Crustaceans sometimes eat 
marine vegetables. Many even seem to prefer fruit to animal food. 
Such is the tree-crab of the Polynesian Isles, which feeds almost 
exclusively on the cocoa-nut. This crab lias thick and strong claws » 
the others are comparatively slender and weak. At first glance it 
seems impossible that it could penetrate a thick cocoa-nut surrounded 
by a thick bed of fibre and protected by its strong shell; hut 
M. Liesk has often seen the operation. The crab begins by tearing 
off the fibre at the extremity where the fruit is, always choosing the 
right end. When this is removed, it strikes it with its great claws until 
it has made an opening ; then, by the aid of its slender claws, and by 
turning itself round, it extracts the whole substance of the nut. 
