Though their general appearance is quite familiar, it is not so commonly known that there are many different varieties of these creatures. As a matter of fact, there are scores of different kinds, some living on the beach, some just below extreme low-water mark, and others in the deep sea. We shall concern ourselves here only with those that live on the beach. There are three common kinds which every one ought to know. Two of these, curiously enough, though _beach_ animals are not really _sea_ animals. They are hardly ever in the water; they live on the fringe of beach which lies just above high-water mark. The sea reaches them but rarely, and they never voluntarily seek the water. These two kinds are known as the shore-hopper (_Orchestia_) and the sand-hopper (_Talitrus_), the latter being found mostly on sandy beaches, where they make little burrows in which to hide, and the former living under stones or among the decaying seaweed on stony beaches. They both get their name of “hopper” from their habit of leaping or springing into the air, by means of which they often avoid capture by enemies. French people call them “sea-fleas.” [Illustration: _Shore-hopper (Orchestia)._ _Sand-hopper (Talitrus)._ _Sholtie (Gammarus)._ (All magnified about three times.)] The third variety, which is probably best known of all, and to which the name of “sholtie” is here more especially applied, is that which occurs farther down on the beach in places which are constantly wet with sea-water. This animal (_Gammarus_) is much narrower in the body than the other two, and some of its legs are bent backwards along its side, so that by means of them it can run or crawl on its side. Indeed, when out of the water this creature in quite unable to walk back uppermost; whenever by any chance it does succeed in raising itself into what is for most animals the normal attitude, it immediately topples over on its side again. It can be readily distinguished from the other two forms by having _two_ pairs of long, delicate feelers or antennæ in front of its head; the hoppers have only one long pair of antennæ and one short pair. All these animals, in spite of their small size, are near allies of the crabs and lobsters. A naturalist would tell you that they belong to the group of the _Crustacea_, this name being applied to all animals of the crab tribe on account of the firm, crackly skin or shell which surrounds them. The Crustacea are marked by other features in addition to the possession of this hard exterior. They are all jointed animals, their body being built up of a series of segments, each of which carries a pair of legs or appendages of some kind, these appendages also being jointed. In the crab and the lobster a number of segments have become fused or welded together to form the front part or body of the animal. In the group of animals to which the sholties belong the segments are all distinct.