Conspicuous Chiton, Stenoplax conspicua, is a representative Polyplacophora of the Ischinochitonidae Family of Chitons.

Mexican Chiton, Onchidella binneyi, is a representative Polyplacophora of the Onchidiidae Family of False Chitons.

The Polyplacophora Class is a very large group of Chiton with 940 know currently living species. The Chitons of the Chitonidae and Ischnochitonidae Families are all within the Subclass Loricata, the Order Chitonida, and the Sub-order Chitonina and Super-family Chitonoidae. The Chitons of the Onchidiidae Family are within the Subclass Heterobranchia, the Infraclass Euthynera, the Subterclass Tectipleura, the Superorder Eupulmonata, the Order Systellommatophora and the Superfamily Onchidioidea. Polyplacophora means “many plates”, referring to the eight, overlapping plates (valves) that comprise these shells. The name chiton (pronounced kite-on) comes from the Greek word for cloak or mantle which refers to the way the hard plates wrap around the animal. Chitons are oval in outline and elongated and flattened, like a limpet and a leathery girdle connects the valves and rarely exceed 6.0 cm (2.4 inches) in length. The dorsal surface of the valve has variable sculpturing is variable but is generally costate with a rough rib-like structure and  resembling a net, and divides the intermediate valves into lateral and central regions as a result of different orientations of the papillae. All valves have insertion plates, the head and tail valves have numerous notches, and the intermediate valves have between one and three pairs of notches depending on the species. The insertion plates are not pectinated. The inner layer of the shell (the articulamentum) produces well-developed sutural laminae on valves two thru eight. Their girdle is covered with scales, spicules and minute hairs and is fringed by bluntly pointed spines. This design allows chitons to flex, and thereby, maintain close contact with curved rock surfaces. This limits their exposure to predators and also to wave action. Chitons are always found on hard substrate. Chitons feed by grazing on algae, small barnacles, bryozonans, diatoms, and hydroids. In turn Chitons are preyed upon by crabs, fish, and predatory mollusks.

The Chitons are found globally, in tropical, temperate, and polar seas. There are about ten Families in the Class and over nine hundred species. They are well represented in the Eastern Pacific and about thirty species, from several Families, are found along the Baja Peninsula. There are about fifty known species in the Ischnochitonidae Family with majority of which are found along the Pacific coast of Mexico.