388 SOLIPEDIA. 
of one of these teeth (fig. 145) from the cavernous fissure, 
a, at Oreston (fig. 50, p. 132); and it is illustrated by 
contrast with the same view of the corresponding lower 
molar of a common Horse of about fourteen hands high 
(fig. 144). Some of the numerous fossil equine teeth of 
large size, from the cave at Kent’s Hole, do not manifest 
this character ; but the large-sized molar teeth of the 
Horse, from the newer pliocene blue-clay at Cromer,* are 
as much narrower transversely, compared with the teeth 
Fig. 146. 
of the large varieties of the 
existing Horse, as are the 
somewhat smaller molars 
from Kent's Hole, Kirk- 
dale, and Oreston. One of 
the Cromer fossil teeth, from 
the lower jaw, with a 
grinding surface measuring 
one inch five lines in long 
(antero posterior) diameter, 
and eight lines in_ short 
(transverse) diameter, pre- 
sented a swelling of one 
lobe, near the base of the 
implanted part of the tooth 
(fig. 146). To ascertain 
; , = the nature and cause of 
Diseased lower molar, Equus fossilis 5 as 
Gpamher al * this enlargement, I divided 
it transversely, and exposed a nearly spherical cavity, 
large enough to contain a_pistol-ball, with a smooth 
* Lyell ‘On the Boulder Formation and Fresh-water Deposits of Eastern 
Norfolk,’ Philosophical Magazine, 1840, p. 361. 
+ I am induced to cite one of the curious examples of disease in an extinct 
animal from the rarity of its occurrence in the tissue which is the subject of it. 
