48 THE AMEEICAI^ BISOIS^S. 



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Explanation of Table X. 



1. Bison americanus, A very old male from Kansas (M. C. Z., No. 95). 



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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. J 0). 



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. 1 



11. Bison americanus. Male, about six yearsold, 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 am,ericanus. 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. 17G8). 



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). 



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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 honasus. Female, about five or six years old (M. C. !Z., No. 1790). 



24. Bison honasus. Old male, from Menagerie of Schoenbrunn (M. C. Z., No. 165). 



25. Bison honasus. Male. Measurements as given by Ki(?hardson, in Zool. Yoy. of the Herald, p. 122. 



26. Bison honasus. Old male, from Shcenbrunn, Measurements as given by Cuvier (Ossem. Foss., 3d 



ed., Tome IV, p. 121). 



27. Bison honasus. 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 VIII 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 simihar difference is trace- 

 able tbroughout the skeleton (see Table IX)^ so that we have individuals 



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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 



