592 Dynamic Theory. 



cornu now seen for the first time in the ascending animal scale. 



Turning now to the ungulates, or hoofed animals, horse, stag, giraffe, 

 &c. , we find the pattern somewhat changed, and one or two significant 

 additions to the convolutions. Fissures 4, 7,7', 

 2, 5, 8, 9, 11, 12, 14, are tolerably constant and 

 common to this group as well as to the carnivores. 

 The direction those take which lie on the top and 

 sides of the hemispheres, is, in the ungulates 

 generally, a diagonal one from behind, forward 

 and inward, while in the carnivores it is more 

 nearly parallel with the longitudinal axis of the 

 brain. In the ungulates fissure 11 appears to 

 be crowded outwards, and two additional fissures 

 inserted between it and the mesial face of the 

 hemisphere. These are the medilateral 10, and 

 the lambdoidal 13. There appears to be a slight 

 intimation of the beginning of 13 in the cat. 

 the a P es is reckoned to 

 be the anterior boundary of the posterior lobe. If so, the ungulates 

 must have the posterior lobe in process of development. It is remark- 

 able that two diverging branches of the mammal class should, as they 



FIG. 315. 



FIG. 312. FIG. 313. FIG. 314. 



FIGS. 312, 313, 314. Side view of brains of Coati, Cat and 

 Fox. ( Owen.) 

 FIG. 315. Inner surface of hemisphere of Cat. 



spread apart take on the same processes of brain de- 

 velopment, even to details as minute as the general 

 convolutions. 



The posterior lobe hinted at in the carnivora, 

 fairly begun in the ungulates, is fully completed in 

 the apes and man. These animals still possess the principal fissures and 

 convolutions of the ungulates, as will be observed by comparing the 

 figures. But there is a remarkable alteration in the direction taken by 

 those in the upper posterior part of the cerebrum. The enormous growth 

 of the convolutions marked p, q, q f , &c., has had the effect to gyrate 

 the posterior ends of fissures 8, 11, 10 and 13 outwards, their anterior 

 ends remaining more or less fixed as pivotal points, as in No. 13, fig. 

 320. ( Cervus.) The same thing has happened, to a certain extent, in 

 the anterior lobe, the great growth of which has pushed back the outer 



