1895.] BRAIN IN THE LEMFES. 147 



with the anterior of the two presylvian sulci found in many 

 Lemurs. A very curious thing about the brain of Galar/o is the 

 very faintly marked antero-temporal furrow. This is so charac- 

 teristic a fissure of the Lemurine brain, and is the only fissure 

 besides the Sylvian which is found in the otherwise smooth brain 

 of Tarsius according to Burmeister's figures. We shall see, 

 ho\\ever, that it is also absent in Cheirogaleus. The parieto- 

 occipital fissure is represented by two small grooves starting from 

 the middle line. The brain of G. montein is not very different, 

 but the dent lying in front of the angular sulcus is absent. 



§ TJie Brain of Cheirogaleus coquereli. (Fig. 5.) 



This brain, as already mentioned, has a rounded form com- 

 parable to that of Loris r/racilis, but it is much flatter, in fact 

 markedly flat. On the upper surface, behind the Sylvian fissure, 

 is a curious hollowing of the brain-surface, which is unlike 

 anything that I have seen in any other Lemur. The cerebral 

 hemispheres diverge from each other very slightly behind, the 

 posterior margin of the hemispheres being almost straight. 



Brain of Cheirogaleus coqiiereli. 

 Lettering as in fig. 1. 



The brain is very slightly furrowed, not nearly so much even 

 as in Loris gracilis, which is, moreover, a smaller brain. The 

 only sulcus which is really conspicuous is the Sylvian. There is, 

 as already mentioned, practically no trace of the antero-temporal. 

 The angular fissures are, however, feebly represented by two 

 short, shallow sulci, not more than gth of an inch in length. 

 They are just in the middle of the brain. 



§ Mutual Affinities of the Genera o/Lemuroidea as indicated 

 hy Brain-structure, 



There is no doubt that the structure of the brain of the Aye- 

 aye, as figured by Owen, justifies the placing of that genus in a 



10* 



