1917] Holden: Osteological Relationships of Beavers LOC 
No. Sex Locality 
Castor subauratus 12654 9 San Joaquin River, near Grayson, 
Stanislaus Co., California 
Castor subauratus 12668 og San Joaquin River, near Grayson, 
Stanislaus Co., California 
Castor subauratus 16385 g San Joaquin River, near Grayson, 
Stanislaus Co., California 
Castor fiber 19229 ? Elbe River, near Wittenberg, Ger- 
many 
There will also be found occasional references to other skeletons 
in the Museum which as yet have not been prepared for study. These 
are: 
No. Sex Locality 
Castor canadensis leucodonta 12107 Alberni, Vancouver Island, B. C. 
Castor subauratus 8988 San Joaquin River, near Grayson, 
Stanislaus Co., California 
Castor subauratus 16382 2 San Joaquin River, near Grayson, 
Stanislaus Co., California 
Castor subauratus 16383 San Joaquin River, near Grayson, 
Stanislaus Co., California 
Castor subauratus 16384 San Joaquin River, near Grayson, 
Stanislaus Co., California 
It has been impossible up to the present time to obtain a skeleton 
of Castor canadensis frondator, which form is found in parts of the 
southwestern United States and barely enters California along the 
Colorado River. 
As far as can be determined from the skeletons, with two excep- 
tions, there is but little difference in age among the specimens of 
subauratus ; no. 12654 is much the oldest, and no. 16384 is a juvenile. 
Among the four representatives of the subspecies of canadensis the 
specimen of phaeus appears to be slightly older than the other three. 
ACKNOWLEDGMENTS 
It is proper to make acknowledgment here of many suggestions 
kindly proffered by Professor William E. Ritter. The writer would 
also extend thanks for various suggestions to Professors John C. Mer- 
riam, Charles A. Kofoid, and J. Frank Daniel, as well as to Doctors 
Joseph Grinnell and Walter P. Taylor, of the staff of the California 
Museum of Vertebrate Zoology. 
