^6 Journal of Comparative Neurology. 



In 1878 Broca (4, 645) said the insula of the gorilla bears 

 " three gyres as in the orang, while there are four in the chim- 

 panzee." Chapman in 1879 (g, 61) said: "The central lobe, or 

 island of Reil, which is very slightly convoluted, is entire con- 

 cealed in the chimpanzee." 



Spitzka (56, 255) says that the gyres of the orang's insula 

 correspond as to their direction and relations to those of man, 

 though less marked. He further states that " in every anthro- 

 poid dissected by myself, I find these gyri and sulci ; and one 

 sulcus is a constant feature of even the Cynocephali." 



The specimen here shown (Fig. 7) does not exhibit an 

 area so well marked as those described by the above authors 

 and this is probably due to the undeveloped state of the chimpan- 

 zee brain at this age. Excepting the circuminsular, the fissures 

 of the insula are very rudimentary and few in number. This 

 insula was entirely concealed within the Sylvian fissure. There 

 seems to have been a feeble attempt at producing a transinsular 

 fissure but no apparent approximation to a pole. Broca (4, 369) 

 says: " L'insula est toujours simple chez les cebiens et les pith- 

 eciens, ainsi que chez gibbons. Chez les grands anthropoides 

 et chez I'homme, elle se subdivise en un certain nombre de plis 

 qui convergent vers le pole et vont gagner successivement les 

 divers points de la rigole superieure, qu'ils traversent pour se 

 Jeter profondement dans le lobe frontal." 



Marchand (30, 1893) says: " In the lower apes the isle 

 of Reil is exposed. This is the case in microcephalic idiots." 



Spitzka (66, 173) has shown that the claustrum in present 

 in the baboon and that it is similarly located to that of man. 



The insula of the macaque monkey (Fig. 8) shows a well 

 rounded eminence deeply imbedded in the Sylvian fissure. It 

 is sharply demarcated by the circuminsular fissure but is other- 

 wise unfissured and is' about twice as long as broad. 



Cercoccbtis ftiliginostis ^r^scnis an insula very similar to that 

 of the macaque. It, like the last-named, shows a well-rounded 

 eminence and a well-defined circuminsular fissure. The insula 

 was deeply imbedded in the Sylvian fissure. 



There are several lemurine brains in the Cornell Museum, 



