TO THE LOWER ANIMALS 283 



ape's brain is not likely to give a very valuable opinion 

 respecting the posterior cornu or the hippocampus minor. 

 If a man cannot see a church, it is preposterous to take 

 his opinion about its altar-piece or painted window so 

 that I do not feel bound to enter upon any discussion of 

 these points, but content myself with assuring the reader 

 that the posterior cornu and the hippocampus minor, have 

 now been seen usually, at least as well developed as in 

 man, and often better not only in the Chimpanzee, the 

 Orang, and the Gibbon, but in all the genera of the old- 

 world baboons and monkeys, and in most of the new- 

 world forms, including the Marmosets.* 



In fact, all the abundant and trustworthy evidence 

 (consisting of the results of careful investigations directed 

 to the determination of these very questions, by skilled 

 anatomists) which we now possess, leads to the conviction 

 that, so far from the posterior lobe, the posterior cornu, 

 and the hippocampus minor, being structures peculiar to 

 and characteristic of man, as they have been over and 

 over again asserted to be, even after the publication of 

 the clearest demonstration of the reverse, it is precisely 

 these structures which are the most marked cerebral 

 characters common to man with the apes. They are 

 among the most distinctly Simian peculiarities which the 

 human organism exhibits. 



As to the convolutions, the brains of the apes exhibit 

 every stage of progress, from the almost smooth brain of 

 the Marmoset, to the Orang and the Chimpanzee, which 

 fall but little below Man. And it is most remarkable 

 that, as soon as all the principal sulci appear, the pattern 

 according to which they are arranged is identical with 

 that of the corresponding sulci of man. The surface of 

 the brain of a monkey exhibits a sort of skeleton map of 

 man's, and in the man-like apes the details become more 

 and more filled in, until it is only in minor characters, 

 such as the greater excavation of the anterior lobes, the 

 constant presence of fissures usually absent in man, and 

 the different disposition and proportions of some convolu- 

 tions, that the Chimpanzee's or the Orang's brain can be 

 structurally distinguished from Man's. 



So far as cerebral structure goes, therefore, it is clear 

 that Man differs less from the Chimpanzee or the Orang, 



* See the note at the end of this essay for a succinct history of 

 the controversy to which allusion is here made. 



