AND AFFINITIES OF THE GORILLA. 271 



coextensive backward with the cerebellum, and the beginning of the structures' 

 characteristic of the posterior lobes in Man are determinable. But, for the present 

 zoological application, the following accurate definition by Tiedemann of the Human 

 condition of some of these structures may be relied upon: — "Pedes hippocampi 

 minores vel ungues, vel calcaria avis, quae a posteriore corporis callosi tanquam processus 

 duo meduUares proficiscuntur, inque fundo cornu posterioris plicas graciles et retroflexas 

 formant, in cerebro Simiarum desunt ; nee in cerebro aliorum a me examinatorum 

 mammalium occurrunt; Homini ergo proprii sunt." (' Icones cerebri Simiarum,' p. 51.) 

 With regard to other characters, if the naturalist, seeking the true cerebral endowments 

 of the genus Homo, were to abandon his proper guide, viz. the average condition of the 

 brain in the male sex, and to take the brain of a female of the lowest Papuan or Ethio- 

 pian variety, he would nevertheless find that the primary cerebral convolutions charac- 

 teristic of Man, and widely differentiating his brain, by their number, size, depth, and 

 course, from the Ape's brain, are all present, though they may be marked by fewer 

 secondary fissures^. The cerebrum not only overlaps, but extends beyond the cere- 

 bellum ; and the difference in the proportion of the cerebrum to the cerebral nerves, to 

 the pyramidal bodies, to the bigeminal bodies, to the myelon, is such as to manifest as 

 abrupt a step in development as that which is met with between the Lyencephalous 

 and Lissencephalous types, or between the Lissencephala and Gyrencephala. The extent 

 of difference in the proportion of the cerebrum to the above-cited parts in the different 

 varieties of mankind is small, and with such slight gradational steps as to mark the 

 unity of the family in a striking manner. I therefore conclude that the Human 

 characteristics of the brain afford a zoological character of higher degree and importance 

 than do those of his limbs, and concur in the functional estimate with which Tiedemann 

 terminates his paper on the brain of the Orang: — "The cerebral hemispheres are thus 

 most clearly shown to be essentially the instruments by which, in life, the intellectual 

 functions are performed, since through the large size, circumferential expanse, and 

 elaboration of the cerebrum Man differs from all other animals^." It would seem, 

 moreover, that the numbers of the Archencephala, under their manifold varieties, would 



' " Anfang des hintern, dritten Horns des Seitenventrikels " (Kohl, in Ateles, loc. cit.). " Scrobiculus parvus 

 loco cornu posterioris" (Tiedemann, in Macacus, 'Icones cerebri Simiarum,' foL p. 14, fig. iii. 2). "Diegrossen 

 seitlichen Hirnhohlen bestanden aus dreien Hornern, einem vorderen, mittleren oder absteigenden, und einem 

 hinteren Horn " (Tiedemann, on the Orang; who is, however, silent as to any "hippocampus minor"). It exists, 

 however, in the condition described by Vrolik, as " une eminence que nous croyons avoir le droit de nommer 

 un indice de pes hippocampi minor" (" Note sur I'enc^phale de I'Orang," in Versl. en meded. afd. natuurk. 

 Deel xiii., 1861). 



' The " primary " and " secondary " convolutions and fissures are defined and distinguished in my paper on the 

 Cheetah (Sept. 1833, Zool. Trans, vol. i. p. 134). 



' " So wird dadurch auch evidenteste bewissea, dass die Hemispharen des grossen Hirns vorziiglich als die 

 Werkstatte zu betrachten sind, durch welche ini Leben die intellectuellen Verrichtungen vermittelt werden, 

 dem eben durch Grosse, Umfang und Aussbildung des grossen Hirns unterscheidet sich der Mensch von alien 

 iibrigen Thieren" (loc. cit. p. 28). This remark antagonizes that of BufFon, who, in regard to the Orang and 



