164 
JOUENAL OF MAMMALOGY 
where it fuses with the inner of the two cusplets just described. In 
the calf bison on the contrary, its inception is much more abrupt from 
well up on the front side of the tooth and it is usually separated by a 
deep cleft from the external cusplets. In one specimen (M.C.Z. 112) 
it is so reduced as to be practically lacking but is represented by two 
or three minute denticles. (4) A fourth point of distinction is that 
while in the domestic calf the summit of the anterior crescent is rather 
evenly confluent with that of the posterior (fig. 1, c) in the calf bison 
the two crescents are usually separated by a distinct notch which in 
the slightly worn tooth (fig. 3) becomes less evident. Finally (5) the 
anterior horn of the posterior crescent, when unworn, is seen to extend 
into the peak of the angle formed by the two external lophs (fig. 1, d) 
whereas in the bison it abuts against the posterior inner wall of the 
anterior loph, and, as shown in the slightly worn tooth (fig. 3), fuses 
with it at a short distance below the summit. This feature is also char- 
acteristic of the third milk molar . 
The following measurements of the two posterior milk molars in 
domestic calves and calves of the American bison bring out the slightly 
greater size of these teeth in the latter. The Cape Cod bison teeth are 
the first listed among the bison. It should be added also, that the 
teeth of bison no. 112 of the table, though as small as those of a domestic 
calf, in other respects show the characteristic form of the bison teeth 
to an extreme degree. 
Milk teeth of Bos taurus 
COMBINED 
LENGTH OP 
CROWNS 
dp^-* 
CROWN OP 
dp^ 
CROWN OP 
dp* 
mm. 
M. C. Z. 85 
50 
26 
27 
M. C. Z. 86 
50 
26 
27 
M. C. Z. 1954 
51 
26.5 
28 
M. C. Z. 9408 
50 
26 
27 
Milk teeth of Bison bison 
B. S. N. H 
53.5 
28.5 
28.5 
M. C. Z. 89 
53 
28.5 
29 
M. C. Z. 90 
52.6 
27.7 
27.6 
M. C. Z. 112 
50.5 
26 
27.2 
M. C. Z. 1711 
52.5 
28.2 
29 
Acknowledgments are due the Museum of Comparative Zoology 
for permission to study and record the excellent series of skulls noted 
above. 
