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 Paleoniscus and Amblypterus 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 paleon- 
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 Palwoniscus-teeth in connexion with 
the jaws agree in all respects with the tooth of Ganacrodus, 
even to the absence of enamel on the crown of the tooth. 
Paleoniscus, 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 Pygopterus, 
Amblypterus, Gyrolepis, and Cycloptychius have a perfectly 
similar tip of enamel. This we have determined by our 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 +, Saurichthys t, 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 céne de den- 
tine entoure cette cavité pulpaire de-tous cétés; il est plus 
massif au milieu, l& ot se voit le renflement extérieur, plus 
mince vers la base et vers le sommet, et recouvert en haut 
Wun capuchon en émail, qui occupe a-peu-prés le tiers de 
la dent et forme a lui-seul toute la pointe. En examinant 
: Pamphlet reprinted from the ‘ Trans. of the Odontological Society,’ 
p. 29. 
+ Poiss. Foss. vol. ii. pt. 2. p. 152. 
{ Ibid. vol. ii. pt. 2. p. 153, tab. H. figs. 2-5. 
§ Ibid. vol. ii, pt. 2. pp. 27 and 438, tab. G. figs. 9-12. 
