144 



JIB. F. E. BEBDAllB ON THE 



[Feb. 19, 



§ The Brain 0/ Nycticebus tardigradas. (Fig. 1.) 



There appear to be more differences between the brain of this 

 animal and that of its congener Nycticehus 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 figure^ of N. javaniais. The angular fissure («) is short, 

 but instead of being straight it is crescentic in outline, the con- 

 cavities facing eacli other. The two fissures look like a pair of 

 brackets. The in t'ero- frontal suture (if.) seems to be less conspi- 

 cuous 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 than in N. javanicus and reach the 

 intercerebral sulcus. 



Fig. 1. 



Brain of Nycticebus tardigradus. 



a, angular fissure ; i.f., infero-frontal ; Sy., SyKian fissure ; 

 a.t., antero-temporal ; p.o., parieto-occipital. 



§ The Brain of Perodicticus potto. (Fig. 2, p. 145.) 



This brain differs from that of Nycticehus. The angular fissure 

 (rt) 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 pecuhar S-shaped form that they 

 have in that genus. The infero-frontal sutures, if I am right in 

 so identifying those lettered i.f. in the drawing (^fig. 2), have not 

 the longitudinal direction that they have in other Lemurs. They 

 run almost at right angles to the longitudinal axis of the brain, 

 and are apparently very like those of Callithrlv as figured by 

 Sir Wm. Flower ^. The angular fissure is prevented from joining 

 the infero-frontal by a long straight presylvian fissure {p.s.), which 

 runs up between them. The antero-temporal and Sylvian fissures 



1 Loc. cit. pi. 27. fig. 1. 

 ^ Loc. cit. pi. 27. fig. 11. 



