216 
ACXIN OPTER Y GTI. 
small, widely spaced teeth, mostly circular and conspicuously 
mammillated, disposed in from 7 to 10 irregular longitudinal 
series, somewhat enlarged towards the symphysial margin of the 
bone. 
The dentition of the type specimen measures 0*019 in maximum 
width and 0*045 in length. 
Form. Sf Loc. Lower Portlandian : Boulogne. 
Not represented in the Collection. 
Athrodon intermedius, A. S. Woodward. 
1893. Athrodon intermedins, A. S. Woodward, Geol. 31ag. [3] vol. x. 
p. 434, pi. xvi. fig. 1. 
Type. Left splenial dentition; British Museum. 
Splenial bone comparatively elongated, with large,closely arranged 
teeth, mostly smooth and nearly circular, a few exhibiting an apical 
pit with feebly crimped margin, disposed in about 5 or 6 irregular 
longitudinal series, the largest forming a principal series near the 
symphysial margin of the bone. 
Form, df Loc. Purbeekian : Aylesbury, Buckinghamshire. 
40314. The type specimen, described and figured loc. cit. The 
dentition measures 0*017 in maximum width and 0*03 in 
length. Purchased, 1867. 
Athrodon crassns, A. S. Woodward. 
1893. Athrodon crassus , A. S. AVoodward, Geol, Mag. [3] vol. x. p. 435, 
pi. xvi. fig. 3. 
Type. Bight splenial with abraded dentition; Woodwardian 
Museum, Cambridge. 
Splenial bone short and broad, with large, widely-spaced teeth, 
mostly circular, disposed in about four irregular longitudinal series, 
largest near the middle of the bone. 
The dentition of the type specimen measures 0*02 in maximum 
width and 0*04 in length. 
Form. Sf Loc. Cenomanian: Cambridge. 
Not represented in the Collection. 
Athrodon jessoni, A. S. Woodward. 
1895. Athrodon jessoni, A. S. Woodward, Geol. Mag. [4] vol. ii. p. 208. 
pi. viii. fig. 1. 
Type. Bight splenial; British Museum. 
Splenial bone very robust, but narrower than in A. crassus, with 
