Occasionally there may be found in rain-water puddles and the like, in the South of England, a beautiful, transparent, shrimp-like animal, an inch or more in length, to which the name of "Fairy Shrimp" has been given (Fig. 10). It is known in technical zoology as _Chirocephalus diaphanus_, and is a representative of the subclass BRANCHIOPODA. The members of this group are distinguished from other Crustacea by their flattened, leaf-like feet, each of which is divided into a number of lobes, and has a gill plate on the outer side. In _Chirocephalus_ there is no carapace, and the head is followed by eleven distinct body segments, each bearing a pair of leaf-like, or rather fin-like, feet. The hinder part of the body has no appendages, and ends in a forked tail. In the female a large pouch hangs from the under-side of the body, just behind the limb-bearing part, and is often found filled with eggs. In the male, a pair of remarkable-looking appendages, each shaped somewhat like a hand with webbed fingers, hang in front of the head. These are connected with the antennæ, and are known as the "claspers," from their function in seizing and holding the female. The eyes are set on movable stalks. Those Branchiopoda which, like _Chirocephalus_, have no carapace, form the order ANOSTRACA. [Illustration: _PLATE II_ _Apus cancriformis_, FROM KIRKCUDBRIGHTSHIRE. (SLIGHTLY ENLARGED)] A second order, the NOTOSTRACA, is represented by _Apus cancriformis_ (Plate II.), which occurs in many places in Europe in ponds and puddles, and very rarely indeed in Britain. In _Apus_ there is a large dorsal shield, or carapace, covering the greater part of the body, which consists of a large number of segments (about twenty-eight), and ends behind in a pair of long antenna-like filaments. The fin-like feet are also very numerous (about sixty-three pairs). The eyes are not stalked, but are set close together on the upper surface of the carapace. [Illustration: FIG. 11--_Estheria obliqua_, ONE OF THE CONCHOSTRACA. (After Sars, from Lankester's "Treatise on Zoology.") A, Shell of female, from the side; B, male, from the side, after removal of one valve of the shell. (Enlarged.) _a´_, Antennule; _a´´_, antenna; _ad_, muscle which draws together the valves of the shell; _f_, tail fork; _md_, mandible] The third order of the Branchiopoda, the CONCHOSTRACA (Fig. 11), are not represented in Britain, though several species occur on the Continent of Europe. In these the carapace forms a bivalved shell, completely enclosing the body and limbs, and closely resembling that of a small Mollusc. [Illustration: FIG. 12--_Daphnia pulex_, A COMMON SPECIES OF "WATER-FLEA." MUCH ENLARGED. (From British Museum Guide.) Female carrying eggs in the brood-chamber]