In these crabs, too, we find most interesting instances of protective resemblance to their surroundings. Some of the small, slender-legged species are not to be recognised without a careful search when they are at rest among clusters of sea firs, their thin appendages and small bodies being hardly discernible in the midst of the slender, encrusted branches, and their peculiar forms are still more concealed by their colouring, which generally closely resembles that of the growths among which they live. Further, the carapace of spider crabs is in itself a garden on which thrive low forms of both animal and vegetable life. Minute _Algæ_, and occasionally some of moderate size, are rooted to the shell, often securely held by the aid of the rough hairs and tubercles that are so characteristic of the exo-skeletons of these creatures; and patches and tufts of animal colonies that have found a convenient settlement on the moving bed still further serve to obscure the nature of the living mass below--a mass that is always in danger of becoming the prey of the fishes which inhabit deep water. It is probable, therefore, that this association is one that is beneficial to both sides as far as the animal life is concerned, the lower species serving to disguise the true nature of the crab, thus protecting it from its numerous enemies, while they in return are conveyed, carriage paid, to the feeding-grounds, where they can freely partake of the fragments that become diffused in the surrounding water. Our illustration on p. 288 shows three species of spider crabs, all of which are common on parts of our shores. The Scorpion Spider Crab (_Inachus dorsetensis_) derives its specific name from the fact that it was first found off the coast of Dorset; but it is abundant off many of our shores, both in the south and north, and may frequently be seen entangled among the fishermen’s nets. It may be distinguished from other and similar species by the four spines arranged in a line across the front portion of the carapace, and the five large, pointed tubercles behind them. This species is undoubtedly a favourite food of the cod, for several specimens may often be taken from the stomach of a single fish. The next species--The Slender-beaked Spider Crab (_Stenorhynchus tenuirostris_)--is seldom missing from the dredgings hauled in off the south-west coast, and is fairly common in other parts. Its legs are extremely slender, and bear spines on the inner side, and its body, where free from the incrustations so often covering the carapace of spider crabs, is of a fresh pink colour. The other one shown in the same illustration is _Arctopsis lanata_, sometimes known as Gibb’s Crab, the carapace of which is pointed behind, bears a large pointed tubercle on each side, and is completely covered with a thick clothing of stiff hairs. It is also common on many parts of our coasts, more especially the coasts of Devon and Cornwall.