516 PROF. ST.-GEORGE MIVART ON THE ZLUROIDEA. [June 6, 
backwards, which may be considered as representing the crucial 
sulcus and the calloso-marginal sulcus united. 
Brain of Genetta tigrina, natural size. 
A, dorsal surface. B, lateral external surface. ©, median or inner surface of 
right hemisphere. 
¢¢, corpus callosum ; ems, calloso-marginal sulcus ; ¢, notch representing crucial 
sulcus ; d, depression on superior lateral gyrus; 4g, hippocampal gyrus ; 
i, inferior lateral gyrus; m, middle lateral gyrus; od, olfactory lobe ; 
os, supraorbital sulcus ; s, superior lateral gyrus; Sf, Sylvian fissure. 
In Viverra civetta the crucial suleus is slightly more marked, 
and the supraorbital sulcus rises higher, than in the Genet. The 
calloso-marginal sulcus runs forward and joins the rudimentary 
crucial sulcus. That part of the inferior lateral gyrus which lies 
in front of the Sylvian fissure is as large as, or larger than, the part 
behind the Sylvian fissure, and may be subdivided by a sulcus. 
In Paradoxurus that part of the inferior lateral gyrus which is 
behind the Sylvian fissure is wide, and bears a V-shaped suleus. 
There is hardly even a rudiment of the crucial sulcus. 
In Nandinia the brain is as in Genetta, save as regards that part 
of the inferior lateral gyrus in front of the Sylvian fissure, which part 
is as in Civetta. 
In Arcéictis that part of the inferior lateral gyrus which is behind 
the Sylvian fissure is wide, and bears a V-shaped sulcus; and the 
superior lateral gyrus has additional depressions. The crucial suleus 
is distinct, but small; and the calloso-marginal sulcus joins it and 
