TEE CEREBRUM. 



799 



an-anged in exactly the same maniier as in the Ox, as may be seen in comparing 

 Figs. 442 and 443. 



Pig. — The cerebellum is flattened before and beliind, against the base of the 

 brain. The latter is much more elongated than in Ruminants. The convolutions 

 are much more simple and less undulating than in the brain of the Ox and Sheep, 

 and in this respect they establish a kind of transition between Ruminants and 

 the Caniivora. In front of the 



crucial fissure there is a deep 

 incision on the upper border of 

 the hemisphere, and which is 

 continued by a fissure between 

 the two frontal convolutions to 

 tlie anterior extremity of the 

 brain (Fig. 444). 



The gyri fissures — those 

 which separate the convolutions 

 of each lobe — are larger than in 

 the Horse. 



The convolutions of the frontal 

 lobe are here also three in num- 

 ber. The ascending frontal and 

 first frontal show scarcely any 

 differences. On the contrary, 

 however, the second frontal 

 passes almost directly backwards, 

 instead of being oblique up- 

 wards and forwards, as in Soli- 

 peds. Simple in front, it bifur- 

 cates behind, and its two branches 

 pass into the ascending frontal 

 convolution. 



There is nothing worthy of 

 remark with regard to the tem- 

 poral lobe, nor to the lobule of 

 the curved plait. 



The first par ieto-occipital con- 

 volution is less distinctly divided 

 into two plaits than in the 

 Horse ; it joins, in front, the 

 first frontal and the ascending 

 frontal convolution. The second 



Fig. 444. 



BRAIN OF TFIE PIG (UPPER FACE). NATURAL SIZE. 



B, Medulla oblongata. C, Cerebellum : 1, middle lobe of 

 ditto ; 2, 2, lateral lobe of ditto. S, Inter-hemispheri- 

 cal fissure : 3, 3, crucial fissure ; 4, 4, deep fissure 

 separating the first frontal convolution, 9, from the 

 second; 12, 13, 5, fissure of Rolando; 6, first parietal 

 convolution; 7, second ditto; 8, limited frontal convo- 

 lution ; 10, annectent gyrus between the limiting fron- 

 tal convolution and frontal convolutions (probably the 

 sigmoid gyrus); 11, lobule of the curved plait. 



offers nothing in particular. 



Dog. — The hemispheres are much more elongated than in the preceding 

 species, except in the Bulldog ; the convolutions are very slightly flexuous. At 

 first sight, it is difficult to find on the brain of the Dog the sulci and lobes dis- 

 tinguished in Solipeds ; but an attentive examination allows it to be approximated 

 to the brains of these animals. 



It is to be noted that the middle branch of \hQ fissure of Sylvius (Fig. 445, 3) 

 is very oblique backwards, which causes the fissure of Rolando to commence 

 much further back than in Solipeds and Ruminants. This fissure at first ascends 



