374 MR. WRIGHT ON THE TEETH 



mentioned when he has overlooked it in the species before us, 

 which is common on most parts of the British coasts. 



The teeth of the Ballan Wrasse are of a bluntly conical form, 

 slightly incurved, and are firmly fixed in the jaws ; they dimin- 

 ish in size from front to back, the posterior being much less 

 than the anterior ; there are also a few smaller teeth in the 

 front of each jaw, slightly within the row of larger ones. The 

 enamel-cap is distinctly seen on each tooth, and in some in- 

 stances the points are much worn. 



The pharyngeal bones, of which there are three, one under 

 and two upper, are covered with teeth, which are also firmly 

 fixed in the bone, and all have the enamel-cap distinctly shown. 

 These teeth vary in form and also in size ; in the under pharyn- 

 geal bone, the teeth in the front are short and stout, of a hemis- 

 pherical form, but passing backward they are smaller and more 

 conical. On the upper phaiyngeal bones some of the larger teeth 

 are of conical form, and have a projecting shoulder at the base 

 of the cap. 



The food of these fishes, consisting chiefly of the moUusca 

 and Crustacea found in their rocky habitats, seems to wear 

 away their teeth very rapidly, and consequently we find that 

 provision is made for their renewal. In the substance of the 

 pharyngeal bones are cavities, in which the teeth are to be seen 

 in process of formation, and as the old ones are worn ofi", the 

 floor of the cavity, with the tooth firmly fixed in it, seems to be 

 lifted to the surface, to occupy their place. 



The teeth in the jaws are also rapidly renewed, and before 

 the old tooth drops ofi" a new one is ready to fill its place. 



On making a section of one of the teeth from the jaws, we 

 find it to be composed of dentine and enamel ; the pulp-cavity 

 occupies nearly the entire length of the tooth, and from it at 

 nearly right angles the dental tubes pass off, a small bundle of 

 them passing into the enamel-cap. A thin film of enamel coats 

 the side of the tooth up to the base of the cap ; the enamel of 

 which the cap is composed is very dense, and in the section is 

 of a brown colour. So thoroughly distinct does this enamel- 

 cap appear to be from the dentine which it covers, that in one 



