CHAP. XXIV. SUB-CLASS OF THE MAMMALIA. 481 



ficial gray matter of the cerebrum, through the number and 

 depth of its convolutions, attains its maximum of extent in 

 Man. 



" Peculiar mental powers are associated with this highest 

 form of brain, and their consequences wonderfully illustrate 

 the value of the cerebral character; according to my estimate 

 of which, I am led to regard the genus Homo as not merely a 

 representative of a distinct order, but of a distinct sub-class 

 of the mammalia, for which I propose the name of '■ Archen- 

 cephala.' "* 



The above definition is accompanied in the same memoir 

 by the following note: — "Not being able to appreciate, or 

 conceive, of the distinction between the psj'chical phenomena 

 of a chimpanzee and of a Boschisman, or of an Aztec with 

 arrested brain-growth, as being of a nature so essential as to 

 preclude a comparison between them, or as being other than 

 a difference of degree, I cannot shut my ej^es to the signifi- 

 cance of that all-pervading similitude of structure — every 

 tooth, every bone, strictly homologous — which makes the 

 determination of the difference between Homo and Pithecus 

 the anatomist's difficulty; and therefore, with everj^ respect 

 for the author of the ' Eeeords of Creation,'-}- 1 follow Linnaeus 

 and Cuvier in regarding mankind as a legitimate subject of 

 zoological comparison and classification." 



To illustrate the difference between the human and simian 

 brain, Professor Owen gave figures of the negro's brain as 

 represented by Tiedemann, an oi'iginal one of a South 

 American monkej^, Midas rufimanus, and one of the chim- 

 panzee, fig. 54, p. 482, from a memoir published in 1849 by 

 MM. Schroeder van der Kolk and M. Vrolik.J 



* Owen, Proceedings of the Linnaan J Comptes rendus do I'Aeademio 



Society, London, vol. viii. p. 20. Royale des Sciences, voL xiii. Am- 



f The late Archbishop of Canterbury, sterdam. 

 Dr. Sumner. 



