OF THK BALLAN WRASSE. 375 



of the teeth I examined it easily came off, and in section is like 

 the barbed head of an arrow. 



In the pharyngeal teeth there is the same structure, the same 

 thin film' of enamel on the sides, and the same dense enamel- 

 cap ; but the pulp- cavity is entirely filled by the substance of 

 the pharyngeal bone. 



In a short treatise on the teeth, by Professor Owen, published 

 in 1854, he states that the pharyngeal teeth of the Wrasse are 

 examples of teeth in which only one of the dental tissues is to 

 be found. He also, in his "Odontography," gives a figure of 

 what he terms a large species of Labrus ; but in neither case 

 does he mention the species he examined, and it is evident, from 

 what I have laid before you, that his description and figure will 

 not apply to the teeth of the Ballan Wrasse, in which we find 

 both dentine and enamel ; and the manner in which the teeth 

 are fixed to the pharyngeal bone is very different to that figured 

 by the Professor. 



Whether the structure I have endeavoured to describe is cha- 

 racteristic of the Labroids, I have not had the means of deter- 

 mining ; but should opportunities offer of examining other species 

 of the family, I shall be glad to lay the results before the Club. 



The accompanying plate is from a drawing by Mr. William 

 Dinning, to whom my best thanks are due. 



EXPLANATION OF PLATE XV. 



Fig. 



1 



Fig. 



2. 



Fig. 



3. 



Fig. 



4. 



Tooth of Ballan Wrasse, natural size. 



Magnified section of the same : «, enamel-cap ; h, thin film of 

 enamel coating the sides of the tooth ; c, pulp cavity ; f/, dentine. 



Pharyngeal tooth of Ballan Wrasse, natural size. 



Magnified section of the same: a, enamel-cap; h, thin iilm of 

 enamel coating the sides of the tooth ; c, pulp cavity filled wiili 

 the substance of the pharyngeal bone ; d, dentine. 



