FORM. 



has attracted the attention of most comparative anatomists, and yet 

 such is the rapidity with which new species, either of the present 

 or a past creation, are added to the catalogues of the ichthyologist, 

 that this part of the subject is far from being exhausted. All the 

 known differences which the teeth of fishes present in this respect 

 may, however, be referred to modifications, either of the cone, the 

 plate, the prism or the cylinder. 



The conical teeth may be slender, sharp-pointed, and so minute, 

 so numerous, and closely aggregated as to resemble the plush or pile of 

 velvet; these will be termed villiform teeth, they are the dents en velours 

 of Cuvier, and are sometimes so short as to be more easily felt than 

 seen : when the teeth are equally fine and numerous but longer, they will 

 be called ciliiform teeth : when long and slender, but a little stronger, 

 they are the dents en brosse (brush- teeth) of Cuvier. Conical teeth as 

 close-set and sharp-pointed as the villiform teeth, but of larger size, are 

 the dents en rape, or en cardes of the French anatomist. These modifi- 

 cations of the whole or a part of the dental series are common to 

 a great number of fishes. The perch has all its teeth en velours ; the 

 pike presents the rasp-like teeth on the posterior part of the vomer ; 

 the armature of the palate bone of the silurus (PI. I, fig. 1,) as well 

 as that of other bones of the mouth of the same fish, presents all the 

 gradations between the dents en velours, and the dents en cardes. 



The conical teeth may be so long and slender as to resemble 

 bristles, as in the chsetodonts (PI. 1, fig. 2.) These setiform teeth 

 are sometimes bifurcate at their free extremitv, as in the 2;enus 

 Citharina ; or they may terminate in three diverging points, as in 

 the anterior maxillary teeth of the genus Piatax (PI. 1, fig. 2*), and 

 here the cone merges into the long and slender cylinder. Or the 

 elongated cone may be compressed into a slender trenchant plate ; 

 and this may be pointed, recurved, or even barbed like a fish hook, as 

 in the Trichiurus (PL 1, fig. 8,) and some other scomberoid fishes ; or 

 it may be bent upon itself like a tenter-hook, as in the Pimelipterus 

 and Gonyodontes. In other species as in the bonito, (PL 1, fig. 3,) the 

 conical teeth present a progressive thickening of the base, and this 

 modification being combined in certain predatory fishes with an 

 increase of size and a slightly recurved direction, they resemble the 



