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It is essential for accurate identifications to refer to one or more of the ten technical terms used in describing the various parts of the chiton. A few minutes’ study of figure 18 will prepare the reader for the photographs, identification drawings and descriptions of the species. Jumping to conclusions from the photographs instead of ascertaining the family or genus first will lead to discouraging results.

All the chitons discussed in this book bear eight shelly valves which cover the body of the creature and are bound together by a leathery girdle. The chitons without valves (Aplacophora) are too rare to be conveniently included here. A view of the underside of a living chiton will show the rather small, separate head and its mouth and, behind this, the larger, oblong foot. On each side of the foot is a straight row of closely packed gills. The head bears no tentacles or eyes, although the valves of many chitons bear numerous shell eyes.

Each chiton possesses three types of valves: (1) the anterior valve at the head end, (2) six intermediate valves, and (3) the posterior valve at the hind end. The shape and ornamentation of these valves are used for identification purposes, and for this reason the various areas of the valves have been named. Removal of the last two valves by the soaking of dried