1893.] BRAIN OF THE AFRICAN ELEPHANT. 313 



T-shaped fissure running at right angles to the longitudinal axis 

 of the brain ; one of these, but I am not sure which, is probably 

 the pre-Sylvian fissure (Plate XXIII. fig. 1, P.s). 



The front aspect of the brain is marked by two principal fissures, 

 of which the innermost (that nearest the interheraispheral sulcus) 

 appears to me to be the anterior termination of a more or less 

 strongly marked furrow running on the dorsal aspect of the hemi- 

 sphere for more than the anterior half at a distance of rather less 

 than an inch from the interhemispheral sulcus. The second of the 

 two fissures observable on the frontal lobe of the brain is almost 

 as far from the last mentioned as from the Y-shaped fissure referred 

 to above. This fissure seems also to be the anterior end of another 

 longitudinal furrow, which curves round posteriorly and is con- 

 tinuous with the first of the two fissures dividing the temporal 

 lobe of the brain longitudinally. 



The temporal lobe is divided by two furrows, of which the 

 anterior is approximately equidistant from the anterior margin of 

 the temporal lobe and from the posterior furrow, into three gyri — an 

 antero-temporal, a medio -temporal, and a postero-temporal. The 

 posterior temporal fiss\ire (Plate XXIII. fig. 1, P.t) curves over the 

 hemisphere and divides off an occipital lobe, becoming continuous 

 with the sulci of the inner face of the hemisphere. The anterior 

 temporal furrow bends round and forms the posterior of the three 

 branches of the Sylvian. 



Left Hemisphere. 



The left hemisphere of the brain (Plate XXIII. fig. 2) shows 

 many detailed differences from the right ; in more complicated 

 brains there is of course usually such an asymmetry ; the existence 

 of this asymmetry, however, perhaps enables one to abstract from 

 a consideration of both halves of the brain a list of the more im- 

 portant furrows. 



On the upper surface of the hemisphei-es the two longitudinal 

 furrows are not recognizable anteriorly ; they are lost by the more 

 marked cross furrowing. Posteriorly, however, the outer of the 

 two is very deep, and, therefore, conspicuous ; it is continuous, as 

 on the right side, with the middle temporal fissure. Both the tem- 

 poral sulci are as pronounced on the left side as on the right. The 

 fissure of Rolando, however, if I am right in so identifying it, is 

 by no means so extensive on the left side. It seems to be divided 

 into two tracts, of which that continuous A^-ith the Sylvian is the 

 deepest ; the upper half comes to within about the same distance 

 of the internal margin of the hemisphere. Anteriorly there are 

 the same two Y-shaped fissures, of which the first (counting from 

 behind forwards) is, as on the right hemisphere, the deeper. The 

 temporal fissures are as on the right side. 



Cerebellum. 



The cerebellum is neither figured nor described by Krueg. As 

 shown in the accompanying drawing (Plate XXII.), it has a narrow 

 median lobe, which is visible in the cerebellum only as seen from 



