Proceedings of the general meetings for scientific business of the Zoological Society of London, 1895

Page 178

144 ME. F. E. BEDDAED ON THE [Feb. 19, § The Brain of Nycticebus tardigradus. (Fig. 1.) There appear to be more differences between the brain of this animal and that of its congener Nycticebus javanicus than between the different species of Lemur that I have examined. To begin with, the brain is more rounded in front and the cerebellum is more fully exposed than is indicated in Sir W . Flower's figure1 of N. javanicus. The angular fissure (a) is short, but instead of being straight it is crescentic in outline, the con­cavities facing each other. The two fissures look like a pair of brackets. The infero-frontal suture (if) seems to be less conspi­cuous than in the other species of the genus, and on one side of the brain it ran back to join the curved (anteriorly convex) presylvian fissure, the homologue (?) of which latter in N. javanicus has a totally different direction. The parieto-occipital (" Simian") (p.o.) fissures are better developed thau in N. javanicus and reach the intercerebral sulcus. Fig. 1. Brain of Nyctie-ebus tardigradus. a, angular fissure; If., infero-frontal; Sy., Sylvian fissure; a.t., antero-temporal; p.o., parieto-occipital. § The Brain of Perodicticus potto. (Fig. 2, p. 145.) This brain differs from that of Nycticebus. The angular fissure (a) begins further back, well behind the extremities of the Sylvian and antero-temporal fissures, which are curved outwards as in the genus Lemur, but have not the peculiar S-shaped form that they have in that genus. The infero-frontal sutures, if I a m right in so identifying those lettered if. in the drawing (fig. 2), have not the longitudinal direction that they have in other Lemurs. Thev run almost at right angles to the longitudinal axis of the brain and are apparently very like those of Callithrix as figured by Sir W m . Flower 2 The angular fissure is prevented from ioining the infero-frontal by a long straight presylvian fissure (».«.), which runs up between them. The antero-temporal and Sylvian fissures 1 Loc. cit. pi. 27. fig. 1. 2 Loc. cit. pi. 27. fig. 11.