XX. A description of the teeth of the Anarrhichas Lupus Linn and of those of the todon nigricans of the same author; to which is added, an attempt to prove that the teeth of cartilaginous fishes are perpetually renewed.

Abstract

The external variety there is in the external form of fishes must be obvious to a common observer; and whoever examines will be convinced, that the same variety prevails in their internal structure. No parts, perhaps, affords a more convincing proof of the last assertion than the teeth of fishes. To adduce a few instances, let us only recollect the tuberculated teeth in the thorn-back; the triangular serrated teeth in the shark; the slender flexible teeth in the <italic>chætodontes</italic>, or angel fishes. There is not only a difference of their form, but also in the substances of which they are composed; some being of a soft horny nature; other made up of bone; other of that substance we call enamel in the teeth of quadrupeds; and some having the apparent hardness and transparency of crystal. We may also notice their uncommon situation; many fishes have teeth not only in their jaws, but on the tongue, the palate, and about the <italic>fauces</italic>.