348 DAVIDSON BLACK 
a characteristic ungulate fashion. There is no indication of an 
arcuate constellation between the long processus acuminis and 
the suprasylvian sulcus. 
Variations in cortical pattern in the Bovidae 
Although most members of this family conform more or less 
closely to one or other of the types of cortical pattern above 
exemplified, several exceptions are to be noted. Thus, the black- 
buck (Antilope cervicapra), the guib (Tragelaphus scriptus), 
the kudu (Strepsiceros kudu) and the eland (Taurotragus oryx) 
are each characterized by the shortness of the pseudosylvian 
processus acuminis and the development, between this sulcus 
and the dorsally placed suprasylvian, of a well marked com- 
pensating arcuate constellation (9, pp. 336 and 338). 
(3) Cervus virginianus (figure 12). The operculation in the 
pseudosylvian region is rather more advanced in the deer than in 
the ox and sheep. The free extremities of the ectosylvian sulci 
are evident, however, as the ramus anterior and_ posterior 
respectively. 
The presylvian is continuous with the coronal, while the lat- 
ter sulcus is in turn joined to the suprasylvian by the arcuatus. 
The diagonal is independent of the suprasylvian. 
The descending ramus of the suprasylvian may be represented 
by the slight notch labelled as such in figure 12, but among the 
Cervidae this sulcus is either absent or but poorly developed, as 
frequently is the case in the Bovidae. The caudal bifurcation 
of the suprasylvian is well marked. The oblique sulcus is large 
and irregular in this form as in most of the Cervidae. It is pos- 
sible that certain inconstant sulci behind the oblique may rep- 
resent the triradiata posterior. 
The long processus acuminis almost meets the suprasylvian. 
This is a characteristic phenomenon in Cervidae and precludes 
the formation of an arcuate constellation. 
(4) Sus communis (figure 13). The operculation in the 
pseudosylvian area has progressed so far in Suidae that as a rule 
