20 ON THE BRAINS OF MONKEYS. [Jan. 20, 
The parallel sulcus extends considerably beyond the Sylvian 
fissure, and does not—as is so commonly the case with the 
Macagues—join that fissure dorsally. An interesting fact about 
this fissure is that it bends forward at its dorsal extremity, instead 
of being continued on in a straight line. In this bending I see 
a point of likeness to the Semnopithect (cluding Vasalis). No 
absolute distinction between Cynopithecus and Macacus can be, 
however, drawn on account of this furrow, simce Kiikenthal and 
Zichen ‘figure a brain of Macacus inwus in which there is this 
same hending forwards, and, moreover, a bifurcation of the furrow 
superiorly, such as I note in my example of Cynopithecus niger. 
The fissure of Rolando presents no noteworthy characters ; it does 
not nearly cut the inter-cerebral groove. The postcentralis 1s 
better developed on the right side of the brain than on the left, 
and is twansverse in both cases. The precentralis superior is, on 
the other hand, better developed upon the left side than upon the 
right. It is transverse in position. Among Monkeys this fissure 
is more commonly parallel with the long axis of the brain. 
The median parieto-occipital sulcus, visible when the brain is 
bisected longitudinally, presents what I regard as rather an 
interesting and suggestive character. This fissure, in the Macaques, 
&e., has a distinctly forward inclination, often making an angle 
of quite 45° with the vertical. On the oihes hand, in the Raine 
pithect this furrow is nearly vertical (a brain of Vasalis) or with 
a distinctly backward inclination. In Cynopithecus niger this 
same furrow is nearly vertical, but with a slightly backward 
inclination, thus resembling the Semnopithecidee more than the 
Cercopithecidee. 
The calcarine sulcus of Cynopithecus is not at all like that 
furrow in the brains of Cynocephalus, Macacus, Cercopithecus, 
and Cercocebus. In the four last-named genera it is a T-shaped 
sulcus, the cross of the T appearing almost, sometimes in fact 
quite, upon the upper surface of the occipital lobe. This furrow is 
very character istic of those genera. in Cynopithecus the furrow 
is simple and oblique in direction, asit is,as a general sue, among 
the Semnopithecide. 
Tt may be convenient to tabulate the likenesses shown in the 
brain of Cynopithecus to that of Semnopithecus. 
The brain resembles that of the Semnopithecit in :— 
(1) The form of the intraparietal fissure. 
(2) The backward direction of the internal parieto-occipital. 
(3) The absence of any junction between the Sylvian and 
parallel fissures. 
(4) The simple form of the calearine fissure. 
(5) The shortness of the inferior occipital fissure. 
(6) The presence of a well-marked superior portion, and the 
absence of an inferior portion of the inferior temporal 
fissure. 
The first two characters are absolutely distinctive of Cyno- 
