The character which distinguishes the chitons proper from the Oscabrelles (Chitonellus), is that the dorsal plates of shell are comparatively large, much wider transversely than longitudinally, and all in contact with, and overlapping each other. This genus includes a large number of species, which are scattered over all seas, except in the very rocky shore, in greater or less abundance, fast adhering by the broad foot, exactly in the manner of limpets. The largest species are found on the tropical coasts of America, where some attain the gigantic dimensions of four, five, and even six inches in length. The Chiton spiniferus of Chili is said to reach the size last mentioned. The shells are much prized by conchologists, and they are consequently sought by collectors in foreign countries, though the operation is sometimes attended with danger. I have myself collected some kinds, of large size, on the shores of Jamaica, among sharp and rugged rocks, where the surf dashing in breaks over the naturalist at almost every wave, drenching him, of course, and often buffeting him against the rocks, and washing his prize from his hands the very moment he has detached it from its hold.
The mode in which Chitons are procured requires some skill and practice, as if they are touched without being detached in an instant, they increase their adhesion so greatly as to defy all efforts to remove them without lacerating the edges of the mouth, and thus spoiling them as cabinet-specimens. An old knife, that has the tip