346 DAVIDSON BLACK 
TYPES OF FISSURAL PATTERN ON THE LATERAL SURFACE OF THE 
CEREBRUM IN UNGULATES 
Before discussing the possible significance of the data recorded 
in the preceding description, it will be well for the sake of compari- 
son to consider briefly certain types of fissural pattern which 
obtain among ungulates other than the Giraffidae. 
Only the sulci on the lateral surface of the cerebrum in forms 
belonging to the group Ungulata vera (Flower and Lydekker, 
14) will be considered. 
(1) Bos taurus (figure 10). The ectosylvian sulci are hidden 
in the ox for a large part of their extent by the frontal and caudal 
pseudosylvian opercula, which come together and form the large 
processus acuminis. The anterior and posterior rami of the 
ectosylvian may be seen as they diverge from the base of this 
suleus. No doubt can remain as to the identity of these sulci 
since Holl’s interpretation (vide infra, p. 352) has again been 
confirmed by the study of their ontogenetic development (Kap- 
pers,/ive;, p- 289): 
Below the diverging ectosylvian limbs is a somewhat depressed 
area limited ventrally by the rhinal fissure. From this fissure 
a Y-shaped notch extends upward as in the specimen figured by 
Elliot Smith (9, p. 343), and represents the homologue of the 
feline pseudosylvian sulcus. The presylvian arises from the 
anterior rhinal fissure. It is not connected with the ramus 
anterior ectosylvii as is the case in the specimen just cited, neither 
is it connected with the coronal as is often the case in Cervidae 
and other ungulates. 
The diagonal is not connected with the suprasylvian, though 
the latter is linked to the coronal, as is frequently the case in the 
Bovidae and usually so in the Cervidae. 
The suprasylvian sulcus is dorsally placed and gives off several 
secondary sulci. One of these, on account of its depth and its 
relation to the oblique, has been termed the ramus descendens 
suprasylvii in figure 10. A more characteristic arrangement 
obtains on the left side of this specimen, where the short de- 
scending ramus is closely related to a caudally placed upturned 
branch of the oblique. Behind the oblique sulcus an irregular 
