The famous East Indian Cocoa-nut Crab (_Birgus latro_), a kind of intermediate link between the short and long tailed crabs, bears a great resemblance to the paguri. It is said to climb the palm-trees, for the sake of detaching the heavy nuts; but Mr. Darwin, who attentively observed the animal on the Keeling Islands, tells us that it merely lives upon those that spontaneously fall from the tree. To extract its nourishment from the hard case, it shows an ingenuity which is one of the most wonderful instances of animal instinct. It must first of all be remarked, that its front pair of legs is terminated by very strong and heavy pincers, the last pair by others, narrow and weak. After having selected a nut fit for its dinner, the crab begins its operations by tearing the husk, fibre by fibre, from that end under which the three eye-holes are situated; it then hammers upon one of them with its heavy claws, until an opening is made. Hereupon it turns round, and by the aid of its posterior pincers, extracts the white albuminous substance. It inhabits deep burrows, where it accumulates surprising quantities of picked fibres of cocoa-nut husks, on which it rests as on a bed. Its habits are diurnal; but every night it is said to pay a visit to the sea, no doubt for the purpose of moistening its branchiæ. It is very good to eat, living as it does on choice vegetable substances; and the great mass of fat, accumulated under the tail of the larger ones, sometimes yields, when melted, as much as a quart of limpid oil. Thus our taking possession of the Keeling Islands, as a coaling station for the steamers from Australia to Ceylon, bodes no good to the Birgus. The long tail, which the paguri sedulously conceal in shells, serves the shrimps and lobsters as their chief organ of locomotion, for although these creatures have well-formed legs, they make but slow work of it when they attempt to crawl. But nothing can equal the rapidity with which they dart backwards through the water, by suddenly contracting their tail. Thus the Lobster makes leaps of twenty feet at one single bound, and the little shrimp equals it fully in velocity in proportion to its size, and belongs unquestionably to the most active of the denizens of the ocean. It swarms in incalculable numbers on the sandy shores of the North Sea, where it is caught in nets attached to a long cross pole, which the fishermen, walking knee-deep in the water, push along before them. Boiled shrimps are a well known delicacy; and the _Squilla Mantis_ of the Mediterranean, which resembles our common shrimp in outer form, but essentially differs from it in the formation of its branchiæ, which float freely in the water, attached to the abdominal legs, holds an equal rank in the estimation of the South Europeans. [Illustration: Crustaceans and Oysters.] [Illustration: Spotted Mantis Crab.]