: _ the Proboscidians. The caudal vertebrae preserved indicate 
oy and slender tail. 
_ D Teao those of the elephant and the rhinoceros. The 
o is stout, and its entire distal end is occupied by the arti 
ulna has its olecranon portion much compressed. -Its distal ¢ 
: ee much smaller than in Rhinoceros, and has no articular fac for 
82 STRUCTURE ami AFFINITIES OF THE BRONTOTHERIDÆ. 
id placed near the first premolar. The latter is proportiona 
much larger than the corresponding tooth in Titanothert 
The upper premolars have all essentially the same struct 
viz: two external connate cusps, with their outer faces ne 
plane, and two inner cones closely united. The anterior cone 
connected with the opposite outer cusp by a transverse ridg 
which has behind it an elongated depression, more or less divi 
by projections from the outer posterior cusp. In the upper 
molars, the external cusps have their outer surfaces deeply 
cave; while the inner cones are low and separate. The lower ii 
cisors were small, and eyidently of little use. The two next 
symphysis were separated from each other. ‘One specimen in ti 
Yale Museum has the crown hemispherical in form. The low 
incisors are frequently wanting, and in old animals the alv 
may, perhaps, disappear. Careful examination, however, 
usually show indicatións of them. The lower canine is of mo 
ate size, and separated from the premolars by a short diaste 
The lower molars are of the Palæotherium type, and agree esse 
tially with those of Titanotherium. | 
The head in Brontotherium was declined when in its natural 
sition. The neck was stout, and of moderate length. The 
vical and most of the dorsal vertebree are distinctly opisthoce 
The atlas is large, and much expanded transversely. The axis 
massive, and has its anterior articular faces much broader tha 
the Dinocerata. The odontoid process was stout, and ¢ 
The transverse process was small, and apparently imper 
. The posterior articular face is concave, and oblique.. The ej 
yses of the vertebree are, loosely united in most specimens 
_ The limbs of the Brontotheride were intermediate in pr 
oe on cavity is shallow, and the condylar ridge sim 
that of the elephant, but not continued so far up the shaft- 
‘The radins esd stont, and its distal end expa 
ZAR locking series. The y are shor 
p : rt four well developed toes of n 
