62 
CHIMJEROIDEI. 
oral surface below and behind the apex of the anterior outer tritor. 
(?) Palatine tooth with the posterior inner tritor of large size, and the 
median tritor extending further forwards than this ; outer tritor 
much elongated and extending far forwards. (?) Vomerine tooth of 
the typical quadrate outline, with about six uniform tritors upon the 
oral margin. 
Form. 6f Log. Oxford Clay: Oxfordshire and Northamptonshire. 
Kimmeridge Clay : Oxfordshire and Dorsetshire. 
P. 476. Left mandibular tooth, right palatine, and right and left 
vomerine teeth, described and figured by Agassiz, tom. cit. ; 
Kimmeridge Clay, Shotover, near Oxford. Egerton Coil. 
41173, 41226, 41395, 41863-4, 41961. Three mandibular teeth, 
and two pairs of small mandibular teeth; Kimmeridge 
Clay, Weymouth. Purchased , 1868-70. 
P. 1159 a. Small left mandibular tooth ; Kimmeridge. 
Egerton Coll. 
P. 3094. Three mandibular teeth; Weymouth. 
Ennislcillen Coll. 
41174, 41225, 41397. Left palatine tooth, and two imperfect ex¬ 
amples of the right side ; Weymouth. Purchased, 1868-69. 
P. 3093 a. Imperfect left palatine tooth ; Weymouth. 
Ennislcillen Coll. 
41396, 41962. Imperfect right vomerine tooth, and a pair of larger, 
but similar teeth ; Weymouth. Purchased , 1869-70. 
41865. Mandibular tooth of young; Weymouth. Purchased, 1870. 
Ischyodus dufrenoyi, Egerton. 
1843. Chimmra dufrenoyi, Sir P. Egerton, Proc. Geol. Soc. vol. iv. 
p. 155. 
1843. Ischyodus duvernoyi, Sir P. Egerton, ibid. p. 156 {errore). 
1867. Ischyodus dufrenoyi, H. E. Sauvage, Catal. Poiss. Form. Second. 
Boulonnais (Mem. Soc. Acad. Boulogne, vol. ii.), p. 73, pi. iv. 
fig. 12. 
Type. Left mandibular tooth. 
Mandibular tooth much compressed, with a deeply sinuous oral 
margin, a prominent symphysial beak, and the post-oral margin 
much more inclined backwards than the symphysial margin, which 
is gently arched; beak-tritor very small ; outer tritors well 
developed; median tritor occupying the greater portion of the oral 
