Comparative Anatomy of the Brain. 591 



The marsupials add the ectorhinal No. 2 and the sylvian fissure No. 

 5. In some are also found Nos. 8, 9, 10 and 12, not all well developed, 

 however. (See fig. 307. ) In the smaller species of the carnivores, 

 there are to be found Nos. 2, 5, 8 and 14 on the outside, and on the 

 mesial face are the hippocampal No. 4, and the callosal No. 7. In some 



FIG. 307. Top view of Brain of Kan- 

 garoo (Macropus Major). 



of the larger genera are to be 

 found in addition the post syl- 

 vian No. 9, the lateral 11, and 

 the coronal 12. The brain of 

 the seal is one of the most 

 highly developed among the 

 carnivores. The part behind 

 the fissure of sylvius is well de- 

 veloped, and covers more of 

 the cerebellum than is covered 

 in the other carnivora. The 

 large fissures, 8 and 11, divide 

 the principal part of the top 

 surface of the hemisphere into 

 three grand divisions, marked 

 e, g, ?, and named the sylvian, 

 supersylvian, and medial folds. FlQ 307 



Besides these there are numerous small fissures subdividing the cortex 

 into many minor folds. 



The cetacea possess a high development of brain, and the dolphins 

 preserve a resemblance to the seal in the three great longitudinal folds, 



FIG. 308. Top view of 

 Brain of Stoat. ( Putor- 



FIG. 309. Top of Right 

 hemisphere of Coati. 

 FIG. 310.- Same of 



e, g, I. These, how- 

 ever, are so inter- 

 sected by minor fis- 

 sures that dissection 

 is required for their 

 identification ; the 

 cleft of the primary 

 ones being deeper 

 than that of the min- 

 or ones. Fig. 316 

 shows lateral ventricle of the dolphin with its beginning of a posterior 



FIG. 309. 



FIG. 310. 



