ENDOCRANIAL ANATOMY OF FOSSIL MAMMALS 359 
The artificial cast (fig. 16), however, does show something of its 
form and relations to the cerebrum. ‘The broad widely arched 
lobus anterior is partly hidden by the cerebrum. Its detailed 
structure was doubtless partly impressed on the osseous ten- 
torium, which is lost. As compared with Hoplophoneus (fig. 9) 
the lobus anterior is more hidden in Smilodon. The prominent 
projection Lb.s. (fig. 16) may indicate the lobulus simplex, 
though I am unable to find the sulcus primarius. The general 
shape of the remainder of the cerebellum agrees well with that 
of the lion (Bolk, ’06, fig. 73). A lobulus paramedianus is 
indicated, but not prominent. This lobule seems to have receded 
in phylogeny, being more developed in the ancient forms. Doubt- 
less, the entire cerebellum of this huge ancient cat corresponded 
quite well in most details with that of the modern Felis leo. The 
proportionate size of cerebellum to cerebrum is much greater in 
Smilodon than in the Pleistocene wolf, Aenocyon dirus. 
Cynoidea 
Daphaenus felinus Leidy. The primitive bear-dog, Daphaenus, 
from the Oligocene of South Dakota, is represented (fig. 12) by 
a weathered cast, the description of which would be unpardon- 
able were it not for the fact that the cerebral complexity and the 
cerebellar structures are well shown and their simple and primi- 
tive nature evident. This cast was figured and partially de- 
scribed (Moodie, 716) in connection with a discussion of the 
paranasal sinuses of fossil mammals. The terminology there 
used for the cerebral subdivisions needs revision and a much 
more adequate figure is given (fig. 12). 
Scott (98) has given a figure of a partially exposed brain cast 
of this primitive dog from the left side. In order to have a 
complete account of this interesting brain, I have copied Scott’s 
description: 
Very little can be said concerning the brain, since no complete cast 
of the cranial cavity is available for study. The general shape and 
development of the brain are, however, indicated in the specimens of 
Daphaenus hartshornianus already described. Its proportions are 
very different from those found in existing members of the family 
