48 
Explanation of Table X. 
1. Bison americanus. A very old male from Kansas (M. C. Z., No. 95). 
2. Bison americanus. Male, ten to twelve years old, from Kansas (M. C. Z., No. 91). 
3. Bison americanus. Very old male, from Kansas. 
4. Bison americanus, Very old male, from Kansas (M. C. Z., No. 93). 
5. Bison americanus. Male, about fifteen years old, from Kansas (M. C. Z., No. 10). 
6. Bison americanus. Male, about six years old, from Kansas (M. C. Z., No. 11). 
7. Bison americanus. Male, about four years old, from Kansas (M. C. Z., No. 94). 
8. Bison americanus. Male, about ten years old, from Kansas (M. C. Z., No. 97). 
9. Bison americanus. Male, about twelve years old, from Kansas (M. C. Z., No. 99). 
10. Bison americanus. Male, four or five years old, from Kansas (M. C. Z., No. 100). 
11. Bison americanus. Male, about six years-old, from Kansas (M. C. Z., No. 102).’ 
12. Bison americanus. Male, about twelve years old, from Kansas (M. C. Z., No. 1770). 
13. Bison americanus. Male, about twelve years old, from Kansas (M. C. Z., No. 1771). 
14. Bison americanus. Male, about twelve years old, from Kansas (M. C. Z., No. 1215). 
15. Bison americanus. Male, about fifteen years old, from Kansas (M. C. Z., No. 1216). 
16. Bison americanus. Male, ten or twelve years old, from Kansas (National Mus., No. 12,233). 
17. Bison americanus. Female, four or five years old, from Kansas (M. C. Z., No. 1937). 
18. Bison americanus. Female, about three years old, from Kansas (M. C. Z., No. 1768). 
19. Bison americanus. Female, about three years old, from Kansas (M. C. Z., No. 96). 
20. Bison americanus. Female, about nine years old, from Kansas (M. C. Z., No. 101). 
21. Bison americanus. Female, about six years old, from Kansas (M. C. Z., No. 105). 
22. Bison americanus. Female, about six years old, from Kansas (M. C. Z., No. 92). 
23. Bison bonasus. Female, about five or six years old (M. C. Z., No. 1790). 
24. Bison bonasus. Old male, from Menagerie of Schoenbrunn (M. C. Z., No. 165). 
THE AMERICAN BISONS. 
25. Bison bonasus. Male. Measurements as given by Richardson, in Zool. Voy. of the Herald, p. 122. 
26. Bison bonasus. Old male, from Sheenbrunn. Measurements as given by Cuvier (Ossem. Foss., 3d 
ed., Tome IV, p. 121). 
27. Bison bonasus. Male, about six years old, from the Vienna Museum (National Mus., No. 11,514). 
Individual Variation. —The American bison presents a considerable range 
of what may be termed individual variation. This has already been noticed 
in respect to the metacarpal bones (see Table VHI and Plate X), where it 
was shown that not always the thickest and stoutest examples are the longest. 
Thus a metacarpal of a male 192 mm. in length exceeds in all other dimensions 
another specimen having a length of 213 mm. A similar difference is trace- 
able throughout the skeleton (see Table IX), so that we have individuals 
that present in all parts of their structure a slender or attenuated form, and - 
others that are relatively thick and stout, the tallest and longest specimens 
being sometimes exceeded in stoutness, comparing bone with bone, by 
those of considerably less stature. There are again individuals that differ 
from the average in general bulk, without presenting any other unusual 
differences. Variations in the relative length of the different bones of the 
ee ininrrteremr ere 
