314 ON THE BRAIN OF THE AFRICAN ELEPHANT. [Mar. 28, 



above ; when viewed from behind the median lobe is concealed by 

 the lateral lobes, which completely cover it over. Each of the 

 lateral lobes is divided by a number of deep cross-running furrows. 

 These are placed at irregular interA^als, though parallel in direction ; 

 the cerebellum is thus divided up into a series of flat plates of 

 varying thicknesses. Some of these fissures, which are all very 

 deep, are not continuous right round the cerebellum ; the majority 

 of tliem, however, are. The two halves of the cerebellum are not 

 symmetrical as regards the furrows. 



The plate-like discs, in which the lateral lobes are cleft, are 

 about 18-20 in number. The sjnall median lobe of the cerebellum 

 is in marked contrast to luhat is to be met with i», at any rate, many 

 Ungulates and Carnivora. 



RemarTcs upon the principal Sulci, 



The preceding is, I believe, so far as it goes, an accurate 

 description of the principal furrows. It now remains for me to 

 attempt to determine which are the most important of these. 



Krueg indicates five furrows of first-rate importance in the 

 brains of both African and Indian Elephants : — 



(1) Sylvian fissure, divided below into processus anterior and 

 processus posterior, which join above to form processus acuminis. 



(2) Pre-Sylvian fissure. 



(3) Posterior Siqyra-Sylvian fissure. 



(4) Sutural fissure. 



(5) Coronal fissure. 



The diagrams do not seem to me to bring out close resemblances 

 between the Elephantidse and the other mammals (C«)')j,M'ora, Hyrax) 

 with which they are compared. Dr. Krueg, however, considers 

 that there are no characters peculiar to the Proboscidian brain, but 

 that they approach the Carnivora more neai'ly than they do the 

 Ungulata. 



In the brains of the Carnivora the fuiTOWs on the surface of the 

 brain have an arcuate arrangement round the Sylvian fissure. In 

 the Ungulata, as in the Eodents, the longitudinal fissures seem to 

 be straighter and not to present, at any rate in so marked a degree, 

 an arch-like course. 



I admit, however, that the great development of the temporal 

 lobe in the Elephant is a point of resemblance to the Carnivora 

 (also of course to the Primates, which rather takes away fi'om its 

 significance), and that the furrows of the African Elephant's brain, 

 as 1 read them, are more decidedly arcuate than they are represented 

 to be by Krueg. But it is so extremely difficult to compare the 

 furrows of a complexly convolute brain with those of a smoother 

 brain that I refrain from venturing upon a definite opinion as to 

 the affinities indicated by the study of the Elephant's brain. 



I can identify all the fissures drawn by Krueg, with the exception 

 of the anterior (or posterior, as the case may be) branch of the 

 Sylvian. I could not ste quite so marked a superficial boundary 



