1901.] BKOAD-NOSED LEMUE. 127 



eholedochus arises from the end of the gall-bladder which is turned 

 away from the intestine. 



The hrahi of this species has been figured by Milne-Edwai'ds ; 

 as might be supposed, it hardly differs from that of its congener. 

 Seeing that that of Hapalenmr griseus again is extremely like the 

 brain of the genus Lemur, any differences are scarcely to be looked 

 for. In the brief remarks which follow, the minute divergences 

 in structure between the two species which I record here must be 

 considered to be possibly subject to revision when more abundant 

 material is at the disposal of some anatomist. Since describing 

 the brain of Hapalenmr grisens, I have come into possession of a 

 second brain of that species ; in some respects the second brain 

 differs from that originally described. It is, in the first place, 

 rather larger, a fact which goes some way to removing one apparent 

 difference between the brains of the two species of ffajjalemur. 

 The following measurements of the three brains of which I shall 

 speak here show that the proportions of length to breadth are 

 much the same in the two species ; they are : — 



Leiigtb of cerebral Breadth of cerebral 

 hemispheres. hemispheres. 



Hapalenmr griseus No. 1 33 mm. 26 mm. 



Hapalemur griseus No. 2 35 ,, 28 „ 



Hapalenmr simus 40 ,, 31 „ 



The contour of the brain hardly differs in the two species nor 

 the proportions of the several regions. The accompanying drawing 



Text-fig. 24. 



Brain of Haj^alemur simus. 



A. Dorsal view. B. Lateral view. 



A, supra-angular fissure ; S, Sylvian fissure ; A.T., antero-teraporal. 



shows the furrows of the brain of Hapalemur simus (text-fig. 24), 

 which differs in some minute particulars from that figured by Milne- 

 Edwards. It will be noticed that the Sylvian fissure is shghtly 

 different in this species. The upper end of that furrow does not slope 

 backwards parallel to the angular fissure as it does in H. griseus. 

 On the contrary, its tendency is rather to bend forwards ; the upper 



