344 ROY L. MOODIE 
There have been in my possession for several years a number 
of endocranial casts of fossil mammals, but I have deferred their 
description for various reasons. Now that Davidson Black has 
described (’20) the endocranial casts of Oreodon so fully, I feel 
that there is a basis for further work by those who have not 
been especially trained in the study of such objects. The field 
of endocranial anatomy is a very special one and considerable 
advance has been made since Scott’s (98) results were published. 
The advancement of knowledge in this field is due largely to the 
work of G. Elliot Smith, Palmer (713), and Davidson Black 
(15, ’20). The change in the conception of the nature of endo- 
cranial casts and their faithful reproduction of the surface of 
the mammalian brain is dated from the actual comparison of 
natural endocranial casts with the brains and artificial casts by 
Davidson Black (’15). The impress which the brain makes upon 
the inner table of the skull varies greatly with the group, and 
in the casts here described it is found to be most strongly mani- 
fested in the Carnivora, reaching its maximum in Smilodon from 
the Pleistocene of California. In a few cases the entire configu- 
ration of the cranium is modified by the contained brain, noted 
especially in Putorius by Schwalbe (’04), where the gyri are 
evident as external elevations on the skull. 
It is manifestly impossible for one who has not been especially 
trained in comparative mammalian neurology to do a great deal 
in the interpretation of these endocranial casts, but I have been 
encouraged to place my results on record for other workers in the 
field. The figures are all accurately done by trained artists and 
all have been carefully checked with the specimens. 
LITERATURE 
An important contribution to the study of endocranial casts 
is that of Tilly Edinger (’21), who has described the natural 
cast of the brain cavity of Nothosaurus, a long-headed reptile 
of the middle Triassic near Heidelberg. This reptile is interest- 
ing in having a huge anteriorly placed pineal opening. Edinger 
compares the ancient cast with that of the modern alligator 
and its endocranial cast, calling attention to the fact that the 
