434 THE CRANIOLOGY OF MAN AND ANTHROPOID APES. 



however, certain tliiit the laroest apes are perfeetlj^ developed when 

 man i.s .still in his youth, and that the ape\s l)rain has I'eached perfec- 

 tion before the period of shedding- its teeth, while in man it then takes 

 its real first step to perfection, men of the same bulk as these apes 

 having- four times as uuich siiperficial brain surface." 



Whatever other functions the anterior lol)es of the bi-ain perform, 

 the specific structure of their cortical nerve elements, in conjunction 

 with those of the other lobes of the brain, controls our associative 

 memory and our higher intellectual faculties. If we study the collec- 

 tion of preparations of the brains of apes in our museum we nuist 

 arriA'e at a similar conclusion to that expressed b}" Professors Edinger 

 and D. J. Cunningham, which is that the g^^ri (or convolutions) of the 

 l)rain of man and of the anthropoid apes are to a large extent similar 

 in anatomical characters, with the marked exception of those con\olu- 

 tions which enter into the formation of the frontal lobes. The supe- 

 rior and the middle gyri of these lol^es in anthropoid apes are alwa^^s 

 much shorter than the}" are in the lirains of average Europeans, and 

 what is of especial importance in the brains of anthropoid apes, the 

 inferior frontal gyri exist only in a rudimentary condition of devel- 

 opment. This deficiency is xevy marked with i-espect to that area of 

 the left inferior gyrus which contains the nerve elements which con- 

 trol our faculty of articulate language. It seems prol)al)le that the 

 rudimentary condition of this gyrus in apes is .therefore the anatom- 

 ical expression of the inferiority of these animals to man in intelligence, 

 our intellectual development depending mainh' on oui- possessing the 

 faculty of speech.'' It may ])e. anthropoid apes having oidy rudimen- 

 tary, if any, specialized areas of the cortical nei've elements which 



" The Cranial Affinities of Man and Apes, by Prof. R. Virchow, ]i. 26. Also Jour- 

 nal of Anat. and Phys., new series, Vol. XIII, p. 275. 



^The Anatomy of the Central Nervous System of Man, Prof. Ludwig Edinger, 

 M. D., translated from the fifth (7erman edition hy Prof. W. 8. Hall, 1889, pp. 194, 

 210. Edinger remarks that "very gradually the mantle of the embryonic brain 

 increases in extent, ascending in the vertebrate series. In the apes belonging to the 

 class of j)rimatesit has attained an e.xpansion which l)orders clo.sely on the relations 

 found in man. Nevertheless, an important factor, besides more unessential relations, 

 still separates it from the stage reached by man. The frontal lobe, still very small 

 in the lower apes, attains a large size in the higher apes, but always remains much 

 inferior to that of man. In man, even, this developmental process is nowise ter- 

 minated as yet. Differences still plainly occur in the region of the frontal lobe 

 which allow us to infer the possibility of further perfecting. The inferior region of 

 the frontal lobe, which (!ontains the centers of articulate speech, and siiows very 

 marked variations in development, is tlie part more particularly concerned." 



Prof. D. .1. Cunningham state.s that "one of tlie most reuiarkal)ie characters of tha 

 cerebrum of the chimpanzee and orang is the total absence of the frontal and orbital 

 opercula," or the pars triangularis, which contains Broca's nerve center for articulate 

 speech. ('()ntril)uti(rtis to the Surface Anatomy of the Cerebral Ilemisplieres, by 

 Prof. I). J. Cumungham, Dublin, 1892, pp. 110, 279, 305, where he states that "the 

 inferior frontal convolution of the ape is very different from that of man." 



