In the class of animal messmates we find also a coleopterous insect that lodges in a manner similar to the paguri, of which we shall presently speak. The female of the _Drilus_, a species allied to glowworms, attacks the snail, and when it has devoured it, instals itself in the shell, to pass through its metamorphoses; when necessary, it frequently changes its shell and chooses successively more spacious lodgings. Like a true Sybarite, the drilus weaves a curtain of tapestry before the entrance of its habitation, and remains there peaceably surrounded by the vestment of its youth. Remarkable examples of free messmates are found more especially among crustaceans. It is well known that this class includes lobsters, crabs, prawns, and those legions of small animals which serve as the police of the sea-shore, purifying the waters of the ocean of all organic matters, which otherwise would corrupt them. They do not, like insects, shine with variegated colours; their forms are hardy and varied, and they are often pleasing on account of the singularity of their movements. Professor Verrill has recently studied some of 14 these creatures, and has clearly shown how interesting they are, not only to naturalists, but to people in general. Crustaceans and worms furnish the greatest number of paupers and infirm individuals; and a great many of them need the continual assistance of their neighbours to enable them to get their living. While other animals advance towards perfection as they grow older, it is far different with many crustaceans, and we should be tempted to refer to the vegetable kingdom many of them at the very period when they are approaching the adult condition. Cuvier placed all the class of cirrhipedes among the mollusca, and the lernæans among the worms. Many of these animals which are but indifferently adapted to live without help from others, have recourse to benevolent neighbours; from one they seek only shelter, from another a part of his booty, from a third both an asylum and protection. They are often reduced to a mere skin; everything else has disappeared, and there remains no proper organ except that which is necessary for the reproduction of the species. Corpulent, blind, impotent, legless cripples, their existence is more precarious than that of those miserable mutilated beings found in our cities; they only live on the blood of the neighbour which gives them an asylum. Yet when they first quit the egg they are all free; they frisk, they swim with the rapidity of lightning, and at the close of life we find them deformed, and crouched in some living refuge, as if a foul leprosy had atrophied within them all the organs which served as a means of communication with the outer world. Parasites and messmates, furnished at first with the same kind of limbs and the same habits, can sometimes only be distinguished from 15 each other when we have made our observations on them in their first swaddling clothes.