Abstract: The gross features of the brain of three species of Snub-nosed monkeys (Rhinopithecus bieti, R. roxellanwe and R. brelichi) distributing in China, were examined with particular reference to the fissural patterns of the cerebral cortex.
It was found that the brain of Rhinopithecus exhibits typical cereopithecids characteristics and the cerebrum especially exhibits the typical colobine sulcal pattern as follows:
(1) The course of the rectus sulcus is relatively straight and does not diverge much from the orbit while both the intraparietal and lunate sulci arched. (2) The paths of the Sylvian and superior tempotal sulci are relatively parallel. (3) Both the paroecipitalis and the superior branch of the lateral calcarine sulcus are present. (4) The fronto-orbitalis is infrequently present while occipitotemporal sulcus is not visible in lateral views.
In comparison with the other cercopithecids, the fissural pattern of Rhinopithecus is more complex than that of Presbytis, Macaca and many other genus of ceroopithecids. Thus the observations here in noted and the relevant comment made on them led to the inference that amon'g al the cercopithecids the snub-nosed monkey probably shows the highest cerebral development.
The cerebellum of Rhinopithecus is similar to those of other cercopithecids, but it has the lesser size of the folium and tuber when compared with Macaca and Presbytis. The brain-stem does not call for any special remarks.

Key words: Brain; Morphological characteristic; Rhinopithecus; Primates