THE AMERICAN BISONS. Al 
Their more sheltered and in some other respects somewhat different habitat 
would tend to develop just the differences claimed to distinguish the moun- 
tain and northern woodland race. 
Castrated buffaloes are said to be occasionally met with where the buffa- 
loes are abundant, being castrated when quite young by hunters. They are 
reported to attain an immense size, being so much larger than the others as 
to be conspicuous from their large size. 
Relationship to the Aurochs.—'The American bison is a little smaller 
than the aurochs (Bison bonasus), with a much larger chest, a smaller and 
weaker pelvis, a shorter and smaller tail, more shaggy head, and heavier 
beard. The more important differences, as shown by a comparison of the 
skeletons, consist in the chest (see subjoined measurements, Table 1X) in 
Bison americanus being absolutely larger than in Bison bonasus, while the 
pelvis is very small and weak. The B. americanus is hence greatly devel- 
oped anteriorly, or in the thoracic portion of the body, with. the pelvic 
portion disproportionately reduced, while in B. donasus just the reverse of 
this obtains, —a small compressed thorax and a strong heavy pelvis. This 
gives the aurochs the appearance of standing higher on its legs. The dor- 
sal outline is about equally declined posteriorly in each species, not rela- 
tively much more declined in B. americanus, as generally stated. Neither 
does the aurochs possess relatively longer hind limbs, as compared with 
the fore limbs, than B. americanus, the proportion being essentially the same 
in the two, whether the total height of the animal be assumed as the basis 
of comparison, or whether the comparison be based on the bones of the 
limbs alone. 
Comparing, for example, a fine perfect skeleton of a very large old male 
of each species, beautifully and correctly mounted,* the height of the Ameri- 
can bison at the highest dorsal spine is found to be sixty-six inches; at the 
anterior end of the sacrum, fifty-two inches; which makes the proportion 
between the two measurements as 80 to 100. The height of the aurochs at 
the highest dorsal spine is seventy-three inches; at the anterior end of 
the sacrum, sixty inches; making the proportion between the two meas- 
urements as 82 to 100. This difference is not greater than often occurs 
* These skeletons are Nos. 91 (Bison americanus) and 165 (Bison bonasus) of the osteological collec- 
tion of the Museum of Comparative Zodlogy, both of which were prepared and mounted in the same 
manner by the same persons, under the supervision of Professor H. A. Ward of Rochester, and represent 
two pieces of his best osteological work, which is justly celebrated for its neatness and accuracy. 
