
A Seleton of Great Fossil Beaver, Castoroides Ohioensis. 139 
Without stopping to note all the fragments that have come to the 
knowledge of specialists, let me here name the skull and right 
lower jaw which were found at Clyde, New York, in 1841, and 
which were measured and described many years since by Dr. 
Jeffries Wyman, of Harvard University. 
All who are interested in the literature of the subject, and in the 
enumeration and descriptions of the parts heretofore known, may 
find what they desire in Coues and Allen’s able Monograph on N. 
A. Rodentia, published in the U. S. Geological Survey of the Ter- 
ritories, Vol. XI, 1877. 
Dr. J. W. Jay, of Richmond, Indiana, has a complete lower 
incisor, which was found near Greenville, Ohio, in company with 
mastodon remains, and was described by Dr. F. W. Langdon in 
the JOURNAL of the Cincinnati Society of Natural History, Vol. 
E5228. 
A fragment of an incisor was found in Preble County, Ohio, a 
few years since, and another fragment near Richmond, Indiana ; 
in both instances in connection with Mastodon remains. 
The outer half of a right lower incisor was found several rods 
from the locality of the skeleton now under consideration, and in 
the earth from the same ditch. Said fragment is smaller than 
the corresponding portion of any of the other specimens herein 
named, and the crown seems to have been badly hacked and 
scarred by its opposing tooth. 
Il, ANATOMICAL DESCRIPTION. 
As descriptions of the head have been ably given by others, I 
shall confine my account mainly to parts that heretofore have been 
but little or not at all known. 
It may, however, be of interest to compare a few of the details 
of the jaws and teeth now before me, with the accounts given of 
the same by others, especially where there are slight differences, or 
where certain features may be better developed in this later find. 
As the common beaver is so well known, is accessible, and in 
many respects similar, it may aid both myself and my readers to 
make it a standard of comparison, aiming to show wherein the 
two species approach in structure and where they more widely 
differ. 
