PYCNODONTID-E. 
217 
large, closely-arranged teeth, mostly circular, all smooth, disposed 
in three nearly regular longitudinal series. Anteriorly the three 
series are about equal in size; posteriorly the median teeth are 
slightly the larger. 
Form. Log. Cenomanian : Cambridge. 
P. 7238. The t} T pe specimen, described and figured loc. cit. ; Cam¬ 
bridge Greensand, Cambridge. The dentition measures 
0 - 02 in maximum width and (>04 in length. Jesson Coll. 
The following form of vomer may belong either to Athrodon or 
to Mesodon :— 
P. 7186. Imperfect vomerine dentition, shown of the natural size 
in PI. XVII. fig. 2 ; Portland Stone, near "Weymouth. 
The teeth are widely spaced on a transversely-convex 
surface, and arranged in seven series. All are smooth, 
but much worn; and even the principal median teeth 
are scarcely broader than long. Purchased , 1894. 
P. 3750. Left lateral teeth of a similar vomer ; Portland Stone, 
near Weymouth. EnnisJeillen Coll. 
The following species have also been founded on detached splenial 
bones, of which there are no examples in the Collection:— 
Athrodon boloniensis, H. E. Sauvage, Bull. Soc. Geol. Prance, [3] 
vol. viii. (1880), p. 531, pi. xix. fig. 6.—Lower Kim- 
meridgian ; Brecque-recque, Boulogne. [School of Wines, 
Paris.] 
Athrodon jorofusidens , A. S. Woodward, Geol. Wag. [3] vol. x. 
(1893), p. 435. Pycnodus jprofusidens , J. Cornuel, Bull. 
Soc. Geol. France, [3] vol. v. (1877), p. 609, pi. xi. figs. 3-6. 
Mesodon jprofusidens, A. Gaudry, Enchain. Wonde Anim., 
Foss. Second. (1890), p. 164, fig. 262.—Neocomian ; 
Wassy, Haute Warne. 
Athrodon tenuis , A. S. Woodward, loc. cit. (1893), p. 435, pi. xvi. 
tcmia* 2.—4Lower Senonian^Lonzee,near Gembloux, Belgium. 
[Brussels Eoyal Wuseum of Natural History.] 
Athrodon wittei, H.E. Sauvage, loc. cit. (1880), p. 531. Mesodon 
ivittei, X. Ericke, Palseontogr. vol. xxii. (1875), p. 364, 
pi. xix. fig. 15.—Lower Kimmeridgian ; Hanover. 
An imperfect vomerine dentition from the Cambridge Greensand, 
in the Woodwardian Wuseum, Cambridge, is also not improbably 
referable to Athrodon (A. S. Woodward, loc. cit. 1893, p. 435, 
pi. xvi. fig. 4). 
