THE RAGES OF MAN. 239 



animal which liave, up to this time, been figured or described. The 

 superficial position of the second bridging convolution is evidently 

 less frequent, and has as yet, I believe, only been seen in the brain 

 (A) recorded in this communication. The asymmetrical arrangement 

 in the convolutions of the two hemispheres, which previous observ- 

 ers have referred to in their descriptions, is also well illustrated in 

 these specimens " (pp. 8, 9). 



Even were the presence of the temporo-occipital, or external per- 

 pendicular, sulcus, a mark of distinction between the higher apes 

 and man, the value of such a distinctive character would be ren- 

 dered very douBtf ul by the structure of the brain in the Platyrrhine 

 apes. In fact, while the temporo-occipital is one of the most con- 

 stant of sulci in the Catarrhine, or Old World, apes, it is never very 

 strongly developed in the New World apes; it is absent in the smaller 

 Platyrrhini; rudimentary in Pithecia;* and more or less obliterated 

 by bridging convolutions in Ateles. 



A character which is thus variable within the limits of a single 

 group can have no great taxonomic value. 



It is further established that the degree of asymmetry of the con- 

 volution of the two sides in the human brain is subject to much indi- 

 vidual variation; and that, in those individuals of the Bushman 

 race who have been examined, the gyri and sulci of the two hemis- 

 pheres are considerably less complicated and more symmetrical than 

 in the European brain, while, in some individuals of the chimpanzee, 

 their complexity and asymmetry become notable. This is particu- 

 larly the case in the brain of a young male chimpanzee figured by M. 

 Broca ("L'ordre des Primates," p. 165, fig. 11). 



Again, as respects the question of absolute size, it is established 

 that the difference between the largest and the smallest healthy 

 human brain is greater than the difference between the smallest 

 healthy human brain and the largest chimpanzee's or orang's brain. 



Moreover, there is one circumstance in which the orang's and the 

 chimpanzee's brains resemble man's, but in which they differ from the 

 lower apes, and that is the presence of two corpora candicantia the 

 Cynomorpha having but one. 



In view of these facts I do not hesitate in this year, 1874, to 

 repeat and insist upon the proposition which I enunciated in 1863 :f 



" So far as cerebral structure goes, therefore, it is clear that man 

 differs less from the chimpanzee or the orang than these do even 

 from the monkeys, and that the difference between the brain of the 

 chimpanzee and of man is almost insignificant when compared with 

 that between the chimpanzee brain and that of a Lemur." 



In the paper to which I have referred, Prof, Bischoff does not 

 deny the second part of this statement, but he first makes the irrele- 

 vant remark that it is not wonderful if the brains of an orang and a 

 Lemur are very different; and secondly, goes on to assert that, "If 

 we successively compare the brain of a man with that of an orang; 

 the brain of this with that of a chimpanzee; of this with that of a 

 gorilla, and so on of a Hylobates, Senmopithecus, Cynocephalus, Cer- 



* Flower "On the Anatomy of Plthecia Monachus^ " Proceedings of the 

 . Zoological Society," 1862. 



t " Man's Place in Nature," p. 103, 



