OF THE CEEEBEIJM OF THE QHADEUMANA. 
18T 
were made, and the principal conclusions arrived at, that I met with this passage, which 
affords from an independent source a confirmation of their general accuracy, but at the 
same time leaves untouched the necessity for detailed descriptions of the condition of 
this portion of the brain in particular species. I also think it not improbable that 
renewed investigations into the development of the human brain may necessitate some 
modification in the conclusions contained in the last paragraph. 
Some of the special monographs upon the brains of Quadrumana exhibit discrepancies 
almost equal to those existing in the more general statements upon the subject. Thus 
ScHEOEDEE VAX DEE Kolk and Veoljk found in the Chimpanzee the “ lateral ventricle 
distinguished from that of Man by the very defective proportions of the posterior cornu, 
wherein only a stripe is visible as an indication of a hippocampus minor'*,” while in a 
memoir on the brain of the same animal by Mr. Maeshall, these parts are shown to be 
as fully developed as in an average example in the human brain f. Dr. Rollestox has 
recently described and figured a well-marked posterior cornu and hippocampus minor in 
the Orang J ; and Mr. Huxley, in an admirable memou’ to which I shall have occasion 
hereafter to refer, has given a full account of the structure of the posterior lobes in 
Ateles, a monkey of the Platyrrhine or New World group §. 
Such being the present state of the literature of a subject which is evidently within 
the reach of ordinary observation, it will be seen that its full elucidation must be based 
upon an appeal to nature, and not to authority. Therefore, with a desire to contribute 
some reliable data to an interesting branch of anatomical science, I have taken the 
opportunity recently afforded by the examination of the brains of numerous examples 
belonging to three families of Quadrumana of making the following observations. 
The greater number of the specimens described are from animals which have died during 
the past summer in the Gardens of the Zoological Society. For their transmission into 
my hands while in that perfectly fresh condition so essential to the success of cerebral 
investigations, I am indebted to the attention of Mr. Baetlett, the able Superintendent 
of the Society’s Collection. 
As other considerations besides those of a purely anatomical character have been sup- 
posed to be involved in inquiries of this nature, I must state at the outset that these 
have been undertaken without reference to any theory as to the transmutation of species, 
or origin of the human race ; whatever inferences others may draw from the facts 
related, for my own part I see no reason to assign any special importance, in determining 
the value of such a theory, to the condition of the particular portion of the cerebral 
organization now under consideration, especially as the general close resemblance 
between the physical structure of Man and the Quadrumana has long been a matter 
of common observation. 
As it is to the brain of Man that the comparisons instituted in this paper chiefly refer, 
it will be necessary in the first instance to call attention to certain points in the struc- 
* Nieuwe Yerhandlingen der erste Klasse van Let Eoniogl. Nederlandsche Instituut. Amsterdam, 1849. 
t Nat. Hist. Eeview, July 1861. % Ibid. April 1861. § Proc. Zool. Soc., June 11, 1861. 
2 B 2 
