156 
It is a matter of considerable regret to me, that before concluding 
my notice of the Perissodactyla, I am again compelled to differ from 
that high authority to whom we owe so much, and in whose footsteps 
I may here be said, as it were, to follow. Although I am prepared 
to show that the evidence of the teeth, on which Prof. Owen decided 
the place of his genus Hyracotherium, is not so strong as it may 
appear; yet, on the other hand, their resemblance to those of the 
group to which I must transfer it is not so striking as to have caused 
me in the least to doubt the correctness of the place assigned to it, 
until I was well satisfied of the value of the cranial characters which 
I have pointed out. Although the true molars resemble those of 
the Cheropotamus and other non-ruminant Artiodactyla in the tuber- 
cular form of the four principal eminences, and in having the ridge 
surrounding the base more complete than is usual in the Perisso- 
dactyla, yet to make the resemblance good, they should have, in 
addition to the two smaller tubercles, the one in the front, the other 
in the middle of the tooth, a third one behind; and the fact is well 
worthy of attention, that each of these secondary tubercles is placed 
upon the angle of a bent ridge which connects the pair of larger ones 
immediately behind it, and which in the smaller species (Hyracothe- 
rium Cuniculus) exists, while the little tubercle itself is wanting ; thus 
showing that the ridge is a more essential part of the tooth than the 
tubercle developed upon it; and this ridge just marks out in a rudi- 
mental way the bent transverse ridges in the Rhinoceros, Tapir, Pa- 
leeotherium, and other allied genera. The two last premolars differ 
from the true molars only in the non-development of the inner tubercle 
of the posterior pair, but of which a slight rudiment is still traceable ; 
and the sudden change of form between these teeth and the two first 
is met with in no other genus, either of the Artiodactyle or Perisso- 
dactyle group. This would be perfectly in accordance with law, if 
the third and fourth molars belonged to the milk series, and the ani- 
mal were Artiodactyle ; but the whole series has the appearance of 
adult completeness, and neither the form nor the degree of wear of 
these teeth at all indicates such to be their nature ;—indeed Prof. 
Owen himself never once hints at such an idea. To whichever group, 
then, this little animal be referred, the teeth will present marked ex- 
ceptional characters, and therefore it becomes more necessary to seek 
for further evidence. I was first led to suspect a Perissodactyle affi- 
nity, through observing, by the figures and description published in 
Prof. Owen’s very useful work on the British Fossil Mammalia, that 
the nasal bones exhibit the character of this group in a very decided 
manner, and that the supraorbital foramen and groove are entirely 
wanting. This induced me to examine with care the unique speci- 
men in the Museum of the College of Surgeons, and I thus con- 
firmed these characters, and also found that the mark indicating the 
origin of the obliquus inferior oculi is but a slight depression, not 
more marked than I have seen it in some skulls of Rhinoceros and 
Hyrax, and not placed in a fossa, but simply upon the general uni- 
form concavity. Although the posterior portion of the skull is en- 
tirely lost, yet enough remains to show that there was but a slight 
