270 
sELAcnir. 
Stones field mentioned below. In size they arc as small as the 
teeth of Jf. polijiirion, but seem to be specifically distinsuished by 
the following characters : — Crown of principal teeth high, com- 
pressed, with a largo erect median cone and two or three lateral 
cones, narrow and acutely pointed ; coronal surface of all the teeth 
smooth, except (juite at the base, where vertically wrinkled. Hoot 
depressed, flattened, expanded posteriorly. 
Form. ^ Lor. Hathonian (Stoncsfield Slate) : Oxfordshire. 
33474. Type specimen, shown, of twice the natural size, in I’l. XI. 
fig. 5; Stonosficld. Purchased, 1858. 
39203 a. Less perfect tooth ; Stonesfield. Bowerbank Coll. 
P. 2182 d. Tooth, posterior aspect, shown, of twice the natural size, 
in ri. XI. fig. 6 ; Stonesfield. The root has a consider- 
able rounded posterior extension. Er/erton Coll. 
P. 2845 C. Low-crowned posterior tooth, shown, of twice the 
natural size, in PI. XI. fig. 7 ; Stonesfield. Ihc lateral 
cones are relatively broader and apparently more rounded 
than in the principal teeth. Enniskillen Coll' 
P. 2845 d. Imperfect tooth ; Stonesfield. Enniskillen Coll. 
Hybodus grossiconus, Agassiz. 
1843. Ilyhodus grossiconus, L. Agassiz, Poiss. Foss. vol. iii. p. 184, 
pi. xxiii. figs. 26-41 (.’’fig. 2b). 
1868. Ilyhodus grossiconus, F. A. Quenstedt, Der Jura, p. 348, pi. 47. 
fig. 3.3. 
(1)18.58. Hybodus monoprion, F. A. Queustedt, ep. at. p. 848, pi. 4/. 
fig's. 31, 32. 
1871. Ilyhodus grossiconus, J. Phillips, Geol. Oxford, p. 177, diagr. 
xx.vvii. figs. 4-0. 
(?) 1876. Hybodus polyprion, K. Fricke, Palajontogr. vol. xxii. p. 393, 
pi. xxi. tigs. 17, 18. 
Type. Detached teeth ; School of Mines, Paris ; British Museum ; 
and Caen Museum. 
Teeth with a very high, much compressed crown ; median cone 
very broad and nearly erect in the large principal teeth, narrower 
in the smaller tooth ; lateral cones two or three in number, narrow 
and shaiidy pointed. Coronal surface marked by numerous deli- 
cate vertical wrinkles, extending to the apices in the lateral cones, 
but only reaching the apex of the median cone in the hinder small 
teeth. Root anfcro-postcriorly compressed. 
