AND AFFINITIES OF THE GORILLA. 267 
characters which the modifications of these several structures afford lose any of their 
value, in a classificatory science, through the fact of their being superinduced upon a 
common type. The Seal retains as strongly the peculiarity of the swimming-limb ; the 
Ape has its equally distinctive climbing-limb ; and, in like manner, Man stands alone 
in the possession of limbs for upright station and bipedal progression. Although the 
* astragalus,”’ ‘“‘ hallux,” &c., may be determinable in most Mammalia, a ‘‘ foot,” pro- 
perly so called, is nevertheless peculiar and common to mankind. 
So with the brain and most other organs, although the homologues of the parts in 
Man may not be traceable to the same extent down the mammalian series. Kuhl, e. g., 
in Ateles Belzebuth', Tiedemann in the Macaque’ and Orang ®, Van der Kolk and Vrolik 
in the Chimpanzee*, and myself in the Gorilla®, have severally shown all the homo- 
logous parts of the Human cerebral organ to exist, under modified forms and grades of 
development, in Quadrumana. Nevertheless the distinctive characters of the Human 
brain, such as the manifold and complex convolutions of the cerebral hemispheres, 
their extension in advance of the olfactory lobes and further back than the cerebellum, 
thereby defining a posterior lobe, with the corresponding ‘‘horn of the lateral ventricle” 
and ‘‘ hippocampus minor,” are as available to the zoologist in classification as are the 
equally peculiar and distinctive characters of the calcaneum, hallux, and other struc- 
tures of the foot. 
With regard to the brain, the first element in the present problem which that organ 
yields the zoologist is its early arrest of growth in the Gorilla, as compared with Man. 
In this respect it obeys the same developmental law as the brain in the Chimpanzee 
and Orang’. All Quadrumana, indeed, agree together and differ from Man in this 
respect. 
* Beitriige zur Zoologie und vergleichenden Anatomie, 4to, 1820, zweite Abtheilung, p. 70, tab. vii. 
> Teones cerebri Simiarum, fol. 1821, p. 14, fig. iii. 2. 
* Treviranus, Zeitschrift fiir Physiologie, Bd. ii. s. 25, taf. iv. 
* Nieuwe Verhandlingen der erste Klasse van het Koningl. Nederlandsche Instituut. Amsterdam, 1849. 
* Fullerian Lectures, Royal Institution (March 18th, 1861); reported, with copies of diagrams, in ‘ Athe- 
neum,’ March 23rd, 1861, p. 395. 
° Memoir, No.I., ‘ Osteology of Chimpanzee and Orang-utan,”’ 1835, Trans. Zool. Soc. vol. i. p. 355 :— 
“The brain does not continue to expand after the development of the deciduous teeth.” 
See also the remarks on this subject in the memoir by Professor Eudes-Deslongchamps, who obtained for the 
Museum of the Faculty of Sciences at Caen (of which he is Dean) the body of the first and sole specimen of a 
young Gorilla which reached a European port alive. This judicious naturalist records his impressions on this 
point, and gives the results of his comparisons, as follows :—‘‘ L’encéphale d’un jeune Gorille, Chimpansée, ou 
Ourang-Outang n’atteint point 4 beaucoup prés les dimensions d’un encéphale humain d’un age correspondant 
au leur; il acquiert promptement le volume qu’il doit conserver pendant le reste de la vie; ses enveloppes 
osseuses ont bientét pris une solidité et une épaisseur qui ne permettent presque plus au cerveau de grandir, 
tandis que chez ’homme le cerveau continue de s’accroitre et ses enveloppes de se préter 4 ce développement 
pendant un temps bien plus long que celui qui est accordé au développement du cerveau des singes anthro- 
poides. La téte de ces singes, arrivée 4 l’Age ot toutes les dents de lait sont sorties et en exercice (pls. 3-6), 
VOL. V.—PART IV. 2N 
