BRAIN WEIGHT IN VERTEBRATES 
By ALES HRDLICKA 
The following data on brain weight in vertebrates are a contribu- 
tion to the interesting but not yet ample enough material of similar 
nature that has been gathered in various parts of the world. Since 
the writer assumed the charge of the Division of Physical Anthro- 
pology in the U. S. National Museum, two years ago, one of the 
main objects followed was the gradual establishment of a reference 
brain collection, human and comparative. Due to the generous aid 
received from the National Zoological Park in Washington City, 
the division of Mammals and of Birds in the Museum, the Bureau 
of Animal Industry of the Department of Agriculture, Mr. E. S. 
Schmidt, the principal animal dealer in the city, and with what was 
received from various hunters, it has been possible to examine and 
in most instances preserve the brains of several hundred mammals, 
birds, and other animals. With these were obtained, wherever feasi- 
ble, certain records, among which the condition and weight of the 
body, the sex, the age or stage of life, and the weight of the brain. 
In addition, Mr. Geo. B. Turner, the Museum taxidermist, furnished 
a number of measurements of the bodies. 
The brains were always weighed without the dura mater and im- 
mediately after extraction. No pathological specimens, which for- 
tunately are very rare in animals, were included in the series. 
The data have now accumulated so that they may prove of service 
to others and are therefore here given. They were gathered with 
due care and so far as they go should prove reliable. The identi- 
fications were kindly furnished by Mr. W. L. Hahn and Dr. C. W. 
Richmond, of the National Museum. A difficulty was found in 
some cases in concluding as to the stage of life of the animal, but 
the possible remaining. errors on this account can not be numerous. 
The term “adult” in the records is employed synonymously with 
“full grown.” The considerable source of difficulty and error met 
with in weighing human brains, namely the various grades of con- 
gestion of the organ, is practically absent in the smaller and but 
rarely encountered among the larger animals. It was present, in 
a marked degree, in one specimen only (a harbor seal). 
The records are arranged in two categories. In the first are in- 
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