116 The American Naturalist. [February, 
on regarding his Figure 5 (Plate vii.), where the cortical and 
gyral structure of the so-called commissure are apparent. Now, 
lest it might be assumed that he had a monstrosity * to deal with 
in a single specimen, we find that he had two, a younger and an 
older seal; and furthermore, his artist (Plate 1x., Fig. 6) omits 
the so-called new commissure, furnishing a rather correct repre- 
sentation as I have found it in three brains of the same species. 
From a thorough examination of the brains of two sea-lions 
(Zalophus Gillespiewt) and three seals? (Phoca vitulina), I may 
state the following: The number and complexity of the gyri on 
the mesal face of the seal’s and sea-lion’s brain isas great as in 
the anthropoid brain, and in the frontal region rather more so. 
Where the falx does not intervene, the gyri are bound firmly 
together by the leptomeninges. Like all complexly convoluted 
brains, that of the seal shows considerable asymmetry. In trans- 
section it can be readily seen, even in the sea-lion’s brain, that 
the apices of the gyri of one side interdigitate with the gyri of 
the other, so that a strictly median section might shave off the 
former. If we add to this the presumable* distortion to which 
such a complex brain is necessarily exposed during its removal, 
the likelihood of such an occurrence becomes greatly increased. 
If the intrinsic evidence of Theodor’s paper, which is really 
self-condemnatory, did not suffice to show the fallacy of his claims 
of a commissura suprema, I would add the following : 
1. In six phocidz I have exposed the callosum from the mesal 
fissures, found it contrasting in its brilliant white with the deep 
gray, or rosy gray (according to age and species) of the cortical 
surface, as markedly as in man or the anthropoid apes. 
2. I have found no other commissure dorsad of it, nor any 
2 M fi ion of the g . : 4 sas CA SEIE Re re 11 A ahcent falx 

3 A fourth seal was less EREDA studied, owing to the decomposition of part of the 
brain, although it evy a the gross points herein detailed. With the exception 
of that specimen, which I owed to the N. Y. Aquarium, and one purchased at a fish- 
mongers, all were eke through the kindness of Dr. Conklin, Superintendent of the 
Park Menagerie, in a perfectly fresh condition, being removed from the animals 
within a few hours after their decease, 
t We should hesitate to assume this if the very figures of Theodor did not positively 

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