THE OSTEOLOGY OF HYiiNODON. 
L„„ w.,lch ....y be » the — ‘ The”"!" 
The premelare are very simple I™/. “^"“ the para, and metacones 
arc- umlirniiiislied in number, 0 ‘Jj (tj„g ridge may be observed. 
and in Smopa, as in Hymwdon, ml is much the smallest of the 
Measurements. 
Upper luolar-premolar series, length 
“ prcmolar series, length 
“ molar series, length . 
Diastema behind upper canine 
Upjter premolar 1, length 
“ “ si “ 
“ “ 4 , “ 
“ molar 1, “ 
Dower molar-premolar series, length 
“ premolar series, length 
“ molar “ “ 
“ premolar 1, length 
“ “ 2 , “ 
“ “ 3, “ 
“ “ 4 , “ 
“ molar 1, length 
“ “ 3 | “ 
6- 
u 
a 
j H . HOERIDUS, 
No . 2 . 
H . CRUENTOS, 
No . 1 . 
j H . CKUCIANS. 
p 
< 
H . MUSTELI- 
NUS. 
M . 
0.127 
0.137 
0.106 
0.072 
0.062 
0.058 
.081 
.092 
.068 
.046 
.035 ‘ 
.037 
.046 
.045 
.038 
.026 
.026 , 
.021 
.005 
.005 
.002 
.008 
.002 
.014 
.011 
.009 
.006 
.019 
.015 
.017 
.011 
.0125 
.009 
.022 
.020 
.018 
.011 
.013 
.011 
.019 
.020 
.020 
.012 
.011 
.009 
.016 
.015 
.017 
.012 
.011 
.010 
.031 
.030 
.023 
.014 
.01.35 
.Oil 
.118 
.082 
.077 
.066 
.060 
.047 
.044 
.036 
.062 
.058 
.03.5 
.03.5 
.030 
.011 
.008 
.009 
.005 
.017 
.015 
.010 
.011 
.006 
.020 
.016 
.011 
.0125 
.(K)7 
.019 
.017 
.012 
.0115 
.010 
.014 
.008 
.009 
.020 
.010 
.011 
.009 
.030 
.015 
.014.5 
.011 
' Sitecimeu figured by Leldy, 
II . THE SKULL . 
The skull is in many ways peculiar, with considerable variation among the 
species, and certain almost constant differences between the American and European 
forms of the genus. Schlosser (No. 5, p. 175) points out that among the latter, two 
types may be distinguished. In one the mandible is elongate, with shallow hori- 
zontal ramus, its lower margin is curved throughout its length, and the symphyseal 
region rises very gently. In the other type the horizontal ramus is deep and'mas- 
sive, with almost straight inferior border, and steeply inclined symphysis. In the 
latter tl.e teotli are closely crowded together, 5i has usually a single tang, and JS is 
place.1 oblaiuelj to the long axis of the jaw, while in the former the two anterior 
preniolars ate elongated and isolated. All the known Americnn species are of the 
long and slendcr-jawed type, but H.pmuUem distinctly approximates tile short- 
laced group and the general aspect of its dentition is very suggestive of tl.at of the 
Eumpean yackyrhynch. the obliquely placed tooth, however, is tl.e third 
preinolar instead of the second. 
