1891.] 



MR. F. E. BEDDARD ON HAPALKMUR GRISEUS. 



4.57 



two Lemurs themselves are of about the same size ; but it is interesting 

 to note that the brain of Hapaletmir is distinctly larger \n total size. 

 I cannot compare it with the brain of Lemur anjuanensis, as I did 

 not preserve any record of the measurements of that individual. 



As there is no description, so far at least as I am aware, of the 

 brain of Hapalemur, I have considered it worth to give the following 

 description illustrated by the drawings which I exhibit (fig. 4, 

 A and B). 



The brain of Hapalemur is of an oval form: it is not sharply 

 compressed anteriorly, as is the brain of Lemjir ; neither do the 

 hemispheres diverge from each other so markedly behind as in that 



Fig. 4. 



Brain of Ha-palemur griseus. 

 A, from above ; B, lateral view ; S (in both figures), Sylvian fissure. ^ 



genus and Galago. The convolutions, however, show only slight 

 diiferences from those of Lemur. In Professor Flower's figure of the 

 brain of Letnur nigrifrons^ the angular sulcus is quite distinct from tlie 

 infero-frontal, and I find that this is also the case with Lemur 

 anjuanensis. In Hapalemur griseus these two furrows are present, 

 as shown in the accompanying drawing, and have precisely the same 

 shape as in Lemur ; but there is hardly a break between the 

 anterior end of the angular sulcus and the posterior end of the 

 infero-frontal ; they form practically a continuous sulcus. The 

 Sylvian fissure in Hapalemur extends rather further back than in 

 Lemur., running for a short distance y)arallel with the angular fissure : 

 with the exception of these small difference*, the brains of Hapa- 

 lemur and Lemur appear to me to be very similar. 



Prof. Milne-Edwards has devoted two plates of the magnificent 

 ' Histoire de Madagascar'" to the illustration of the brains of the 

 Indrisinse ; those of the genera Propithecus, Lndris, and Avahi are 

 figured in many aspects. It is quite clear from these admirable 

 figures that while ihere are not wide differences between the Indrisinse 

 and other Lemurs, the brain-configuration of the former shows no 



' "On the Brain of the Javan Loris {Stenoj)s javanicus, Illig.)," Tr. Z. S. 

 vol. V. p. 103. 



- ' Histoire Naturelle etc. de Madagascar,' Manimiferes, Atlas, pis. SO, 87. 



