iv JouRNAL oF CoMPARATIVE NEUROLOGY. 
The volume, we should say, is very nearly an ideally perfect cata- 
logue. With its lucid descriptions and exceptionally clear wood cuts 
it is of great value as a work of reference even to those who do not 
have access to the specimens which it describes. 
At the end of the descriptions of the brains is a summary which 
we venture to quote in full. 
The human brain is by no means the largest known to us. The 
Elephant and the Great Whales possess much larger organs, and even 
the extinct Sirenian AAytina was provided with a brain of larger abso- 
lute dimensions than that of Man. In the case of these huge animals 
the enormous mass of the brain is probably to be explained by the fact 
that the increase in size of the surface of the body necessitates a 
corresponding growth of the neopallium (to which the great proportions 
are chiefly due), which is the ultimate receptive-organ for sensory im- 
pressions. 
In the case of the human brain, however, the Anthropoid Apes 
(which approach near to Man in bodily dimensions) afford us a criterion 
as to the amount of neopallium which may be regarded as ‘‘necessary” 
(in the Family Simiidz) for the reception of impressions coming from 
such an extent of sensory surface as Man possesses. When it is re- 
membered that the largest Ape’s brain is approximately half the size of 
the smallest normal human brain, and the average Gorilla’s brain only 
about one third (approximately) the weight of the average European’s 
brain, it will then be understood how great an area of neopallium (to 
which the disproportionate size of the human and Anthropoid brains 
is chiefly due) Man possesses over and above the needs of the average 
member of the Simiidz, to serve as the physical basis (so to speak) of 
an associative memory of immeasurably greater potentialities (for stor- 
ing and comparing sensory impressions) than that of any other animal. 
The feature, therefore, which distinguishes the human from all other 
brains is the relatively enormous size of the neopallium in comparison 
with the minimum which the forces of natural selection have made a 
condition of survival in a member of the Simiidee. * 
The neopallium assumes important functions and becomes a condi- 
tion of survival for the first time in the Mammalia, and in each succes- 
sive epoch it has become incumbent upon every mammal either, on the 
one hand, to adopt some eminently safe mode of life or some special 
protective apparatus to avoid extinction, or, on the other hand, to 
“cultivate” a larger neopallium, which, as the organ of associative 
memory, would enable it to acquire the cunning and skill to evade dan- 
ger and yet adequately attend to its needs. In many of the Eocene 
Mammalia (cf. the cranial cast of Dénoceras) the neopallium is reduced 
1 IT use the term ‘‘neopallium’”’ (Journ. Anat. and Phys. vol. xxxv, 1901, p. 
431) because the other parts of the pallium, #. ¢. the hippocampus and pyriform 
lobe, do not share in thisincrease. [The significance of the term ‘‘neopallium’’ 
is explained in the article here cited. Cf. also the abstract in this JOURNAL, 
vol. XII, p. xii.—c. J. H.] 
