by which they are encrusted like the rest of the body; and thus their origin is not readily distinguished. Their form is generally exceedingly thin, but being greatly dilated in the vertical direction, and much shortened longitudinally, their appearance, at least in the typical genera, approaches to that of a piece of money, more or less nearly, that is, round and thin. The teeth are fine, long, and slender, resembling hairs collected in several close rows, like the bristles of a brush. The name Chætodon, by which Linnæus designated the whole Family, signifies bristle-tooth, and describes this peculiarity of dentition. The mouth is small, and usually projects in a prominent and pointed snout. The fins are usually much developed, particularly the dorsal and anal, the former of which sometimes terminates in one or more free filaments of great length and slenderness, as in the genera Heniochus and Zanclus, for example. In the genus Psettus, the body is so drawn out above and below, and the dorsal and anal fins are so pointed and hooked, that the fish when laid on its side, bears no slight resemblance to the figure of a bat with expanded wings. Platax has these fins still more enormously lengthened and pointed, as are, in this genus, the ventrals also.
The beauty of these fishes, which are generally of very small size, never fails to evoke the admiration of those who, with eyes opened to the wonderful works of God, visit the shores of the tropical seas. "In the Chætodons," observes an eloquent naturalist, "the seas of the torrid zone possess animals not less ornamented by the hand of Nature [rather by the hand of Nature's Lord],
