362 Messrs. Hancock & Atthey on Reptile- and Fish-Remains 



but they can never for a moment obscure the light derived 

 from a thorough examination of the facts. 



The laniary teeth of Palceoniscus and Amhlypterus agree in 

 all essential characters ; and the tooth of the former is in 

 every respect similar to that of Prof. Owen's " new genus." 

 Consequently this genus can never be adopted by palaeon- 

 tologists. 



With regard to the coating of enamel on the crown of the 

 tooth, on which much stress is attempted to be laid, we can 

 only say, in addition to what has been previously stated, that 

 it is most frequently absent from teeth attached to the jaws, 

 and that by far the greater number of our specimens are de- 

 prived of it, (as we are inclined to believe) from the effect of 

 erosion. Be this, however, as it may, the fact remains un- 

 changed. Authenticated Pal<jeoniscus-i^%\}i\. in connexion with 

 the jaws agree in all respects with the tooth of GanacroduSj 

 even to the absence of enamel on the crown of the tooth. 



Palceoniscus, however, is not the only genus in which this 

 beautiful enamel-cap exists. Although Prof. Owen is pleased 

 to ignore what is stated in the previous " Criticism " on the 

 subject, we here venture to assert that the teeth of Pygoj^terus^ 

 Amhlypterus, Gyrolepis, and Cycloptychius have a perfectly 

 similar tip of enamel. This we have determined by om- own 

 independent research, and can prove the fact by numerous 

 sections of the teeth of all these genera. 



Considerable importance, however, appears to be attached 

 to the supposed novelty of this peculiar tooth-structure in the 

 paper so often referred to. Prof. Owen therein states, on this 

 subject, " that he had not before met with any similar 

 tooth in the whole range of his odontological researches " *. 

 Between twenty and thirty years ago, however, M. Agassiz 

 described and figured the very same structure in the teeth of 

 Pygopterus f, Saurichthys \, Polypterus, and Lepidosteus §, the 

 last two being recent sauroid fishes. 



After giving a full description of the general characters of 

 the tooth of Pygopterus, M. Agassiz says, " Un c6ne de den- 

 tine entoure cette cavite pulpaire de tous cotes ; il est plus 

 massif au milieu, la ou se voit le renflement extdriem*, plus 

 mince vers la base et vers le sommet, et reconvert en haut 

 d'un capuchon en email, qui occupe ^-peu-pr^s le tiers de 

 la dent et forme a lui-seul toute la pointe. En examinant 



* Pamphlet reprinted from tlie ' Trans, of the Odontological Society,' 

 p. 29. 



t Poiss. Foss. vol. ii. pt. 2, p. 152. 



\ Ibid. vol. ii. pt. 2. p. 153, tah. H. figs. 2-5. 



§ Ibid. vol. ii. pt. 2. pp. 27 and 43, tab. G. figs. 9-12. 



