390 KANSAS UNIVERSITY SCIENCE BULLETIN. 
has been very kindly allowed to figure along with the Kansas 
specimen. The only data that seems to be attached to the 
specimen is that it was discovered in Lenawee county, Michi- 
gan, and presented several years ago to the Smithsonian In- 
stitute by Doctor Kost, and now constitutes No. 1634 of the 
Smithsonian collection. 
Of the two skulls figured in this paper, the Smithsonian 
specimen from Lenawee county, Michigan, is by far the more 
complete. This and the skull described by Hall and Wyman, 
and known as the Clyde skull, are the two most perfect speci- 
mens known. The specimen found at Boicourt, Kan., although 
imperfect, still retains enough of the elements of the skull to 
warrant the restoration shown on plate 24, figure 8. 
After a careful comparison between the Lenawee specimen, 
and with descriptions of other specimens, several differences 
occur in the first-mentioned skull which can scarcely be at- 
tributed to either age, sex or individual morphological dif- 
ferences. These variations, in the writer’s estimation, should 
be considered enough of a specific character to determine it a 
different species from C. ohioensis; hence the name C. kan- 
sensis is proposed. 
As a comparison, the well-known skull of Castor fiber has 
been used. 
HISTORY OF THE BOICOURT SPECIMEN. 
The skull figured on plate 26, figure B, was donated to the 
University of Kansas Museum about a year ago by Dr. J. R. Mc- 
Leland, of Pleasanton, Kan. All that can be gathered relating 
to the history of the specimen is that about twelve years ago, 
while sinking coal shaft No. 2, three and a half miles south- 
west of Biocourt, Linn county, Kansas, in the valley of the 
Marais des Cygnes, a miner, Mr. W. J. Thirwell, came across 
the skull at a depth of thirty-four feet, in a layer of sedi- 
mentary material of a bluish color, which overlay a deposit of 
sandy conglomerate. At the time of the find the large incisor 
was complete, and other parts of the skull were present. For 
several years this fine specimen was kept in a cigar store, ina 
case along with the cigar boxes, unnoticed by anyone, until a 
year or two ago Doctor McLeland recognized in it a fossil 
form, secured it, and presented it to the University. 
In the vicinity of Boicourt, and for several miles above and 
below, the river Marais des Cygnes has cut down to an average 
