88 Journal of Comparative Neurology. 



the middle of this area, the base extending in the direction of 

 the length of the area. While this surface is much less fissured 

 than the corresponding surface of the right side, the lateral sur- 

 face of the left side appears much more complicated. In the 

 left insula of the cow (3137) the transinsular fissure was wholly 

 exposed on the lateral surface ; there was no interruption of the 

 circuminsular at the cephalic margin, and the dorsal surface pre- 

 sented five gyres, four of which belong to the preinsula. 



In 1890, Turner (gi, " Fig. 26") gave a wrong idea of the 

 Sylvian fissure (see Fig. 30) in the cow. He mistook the 

 transinsular fissure for the Sylvian. 



In the insula of the cow, individual and lateral variations 

 are perhaps more marked than in that of any other animal ex- 

 amined. We have here exemplified also the peculiar folded 

 appearance first noticed in the bear but more marked. 



The area representing the insula in the burro {Equus asimts) 

 is better developed than that in the deer. It is well rounded 

 and, except at two points along the cephalic boundary, the area 

 is sharply defined by the circuminsular fissure (Fig. 24). As in 

 the deer, the area is divided into a preinsula and a postinsula by 

 the transinsular fissure, the latter area containing but one, while 

 the former consists of four gyres all well developed and sharply 

 defined. There is no approximation to a pole as in man. The 

 location of the area is similar to that of the deer, only the caudal 

 one third lying in the Sylvian fissure. The two most cephalic 

 gyres of the preinsula were exposed before dissection and the 

 plane ot the area makes an angle of not more than 60° with 

 that pf the lateral surface. 



In 187 1, Lussana and Lemoigne (33) stated that the insula 

 of the horse was of considerable size. The writer has exam- 

 ined five brains, two of which, at least, are worthy of descrip- 

 tion. The first was that of a work-horse (2777, R. half) which 

 showed five gyres exposed previous to dissection. Upon dis- 

 section the plane appeared almost perpendicular to the lateral 

 surface, the gyres were six in number and the fifth (from the 

 cephalic end) was subdivided by a small fissure at the mesal 

 end. The fissure separating gyres 2 and 3 is deep, extends 



