486 ON THE RELATIONS OF MAN WITH THE LOWER ANIMALS 
lateral ventricle from above, in a second brain which I possess. This 
brain, which was extracted from a young animal in Africa, was placed 
in rum there, and it was both much discoloured and not so well pre- 
served as I could have wished. The appearances are, however, 
sufficiently distinct to enable me to confirm entirely what I think I 
stated to you before, viz.: 1. The prolongation of the cavity of the 
posterior cornu, to a considerable distance beyond the plane of the 
posterior edge of the corpus callosum (which, I presume, may be 
taken as the best measure of the position of the parts); and 2. The 
existence on the inner side, and partly in the floor of that posterior 
cornu, of an eminence corresponding in all respects with the hippo- 
campus minor... Just as I was setting about the examination of 
this point, I found an opportunity, in my dissecting-room, of looking 
at a fresh human brain, and I thought it might be more satisfactory to 
examine the two brains together. It so turned out, that the brain I 
cut in upon presented an example (not uncommon) of great deficiency 
in the extent of the posterior cornu. I think it is worth sending you 
a sketch of it, for it is really scarcely more developed than that of the 
chimpanzee in this respect.” 
Having now, as I trust, redeemed my pledge to prove that neither 
the third lobe of the cerebrum, nor the posterior cornu of the lateral 
ventricle, nor the hippocampus minor, are structures distinctive of and 
“ peculiar to the genus Homo,” I may leave it to the reader to decide 
the fate of the “sub-class Archencephala,’ founded upon the supposed 
existence of these three distinctive characters. 
And here I might fairly leave the question ; but essential as I have 
felt it to be to my personal and scientific character to prove that my 
public assertions are entirely borne out by facts, I am far from desiring 
to deal with this important matter in a merely controversial spirit. 
Therefore, although the differences hitherto referred to are certainly 
non-existent, I proceed to inquire whether there are any other marked 
and constant characters by which the human may be distinguished 
from the Simian brain. 
Without doubt such characters are to be found; and in all proba- 
bility, as in the case of any other two distinct genera, the more care- 
fully and minutely our inquiries are carried out, the greater will be the 
number of these differentia. So far as my knowledge goes, the most 
prominent and important are the following :— 
1. In the anthropoid apes the brain is smaller, as compared with 
the nerves which proceed from it, than in man. 
2. In the anthropoid apes the cerebrum is smaller, relatively to the 
cerebellum, than in man. 
3. In the anthropoid apes the sulci and gyri are generally less com- 
