492 Dr. F. W. Mott and Miss A. M. Kelley. [ Mar. 6, 
In comparing a lemur’s brain with an ape’s, the difficulty of distin- 
guishing the homologue of the Rolandic fissure presents itself. It has 
been suggested that the small dimple in front of the sulcus lateralis is the 
possible homologue of Rolando; but both stimulation experiments and 
histological examination show that this fissure is within the motor area 
(vide figs. 1 and 2). It therefore does not fulfil the condition of forming 
sy, 
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My 
Fic. 2.—Diagram of Lemur’s cerebrum, seen from above. The motor area, as ascertained 
by the stimulation method, is shown on the right hemisphere. 
the posterior boundary of the motor area which is characteristic of the 
fissure of Rolando in the apes and higher anthropoidea. It seems more 
probable that it is the homologue of the cruciate sulcus of the carnivora. 
Campbell has pointed out that such a homologue exists within the motor 
area in the ape and in man, and finds it in the paracentral lobule. He 
further observes that: “Just as in the lower animals, the deposit of giant 
cells clings to the sulcus cruciatus, so it is with this fissuret; in mapping 
