126° PROCEEDINGS OF THE GEOLOGICAL society. [Nov. 3, 
side, which swelling is present in no Dinotherium, nor m any other 
mammal, save such as have huge canines, requiring that enlargement ; 
but were the swelling of the Coryphodon’s jaw of this nature, it would 
show some trace of the socket of such canzue tooth, which it does not. 
In fact, the only colour to the supposition of the entire tooth in the 
fragment of the jaw of the Coryphodon being an anterior and not a 
’ posterior grinder, is a slight diminution of vertical diameter of the jaw 
beneath the smaller end of the tooth. But the form of the jaw pro- 
duced by such diminution is not very singular amongst extinct pachy- 
derms. M. de Blainville, in repeating my description of the lower 
jaw of the Cheropotamus, says that it is “assez bombée et épaisse dans 
sa branche horizontale, un peu convexe a son bord inférieur, comme 
étranglée a ses deux extrémités et surtout 4 son poimt de jonction avee 
la branche montante.”’ (J. ¢. p. 149.) — 
It is the same character in the lower jaw of Coryphodon that gives 
rise to the posterior constriction manifested in the fragment described 
and figured in my work. ‘The prominence on the outside of the jaw, 
parallel with the hinder division of the last molar tooth in Coryphodon, 
is the commencement of the base of the coronoid process; the inner 
side of the jaw is nearly flat, as is usual m that situation. In his 
criticism of the comparisons which I have made between the Cory- 
phodon and the Lophiodon of Cuvier, I am led to believe that M. de 
Blainville has not rightly comprehended the passage in my work in 
which these comparisons are given, but which he says he has literally 
translated: “dont jai traduit mot 4 mot le passage*.”” My words 
are, alluding to the family-likeness between the parts in the fossil and 
the corresponding parts in the French Lophiodonts, ‘ but the jaw- 
bone below the last tooth in the English fossil is deeper in proportion 
to the size of that tooth than in the Lophiodon Isselanus,” p. 301 ; 
which M. de Blainville renders, “ plus d’épaisseur de la mandibule en 
arriére de la dent enticre, qu’il (M. R. Owen) regarde comme une 
derniére, et proportionellement pour cette dent, que dans le grand 
L. d’Issel+.”’ Thus, a character which I have drawn from the rela- 
tive depth (vertical diameter) of the jaw below the last tooth is changed 
by M. de Blainville into a character taken from the thickness (trans- 
verse diameter) of the jaw behind the same tooth. This puts my 
comparison of Coryphodon with Lophiodon in a different point of 
view from what I intended, or is suggested by the nature of the 
parts; and a reader of the ‘Ostéographie,’ not having my work to 
refer to, would derive an entirely erroneous notion of the grounds on 
which my conclusions as to the relationship of Coryphodon to Lophi- 
odon have been founded. 
This digression also will, I trust, be pardoned, since it relates to 
the establishment of an additional genus of extinct Pachyderms, 
to the restoration of another of the lost forms of our ancient British 
quadrupeds, and to the support of a conclusion, assailed with much 
ingenuity by a deservedly eminent name in osteological science; the 
conclusion expressed by the indication of the genus Coryphodon 
being, also, one which I cannot but regard as important to maintain, 
* Loc. cit. p. 108. + Ib. p. 108. 
