1086 The American Naturalist. [December, 
the apices of these teeth with the cingula. The different degrees of 
development noticed in the superior incisors would seem to indicate the 
order of disappearance of these teeth in the Titanotheride. The 
superior canines are large, pointed, conical teeth, nearly circular in 
cross-section ; they are directed almost straight downward, only slightly 
forward, and scarcely any if at all outward. There is a diastema be- 
tween the superior canines and pm. 1, which is a very simple tooth 
fixed in the jaw by two roots, and consisting of a single cone with a 
posterior heel. The remaining superior premolars and molars are 
wanting in the present specimen. 
The Inferior Dentition :—Of the inferior incisors the median ones 
are much the larger, while the external and internal laterals are about 
equal in size; they all have internal basal cingula. The crowns of 
these teeth are somewhat wedge-shaped, with an anterior and a poste- 
rior inclined plane. The inferior canines are very much like the 
superior, and are directed upward, outward and forward ; they are 
separated from premolar one by a considerable diastema. The latter is 
a very simple tooth, consisting of a single median cone with anterior 
and posterior ridges. In the present specimen pm. y on the right side 
isa much smaller tooth than the one on the left. Pms: ,, s, are be- 
coming molariform, and pm. ; has already assumed the molar pattern.. 
The inferior molars are identical in character with the same teeth in 
Titanotherium and need no further description ; m. , in the type speci- 
men is injured. 
The figures in Plate XXXVIII accompanying this paper, were 
drawn by Mr. Rudolph Weber, and represent accurately the more 
important characters of the skull and lower jaw of the type specimen. 
Figs. 5 and 6 are introduced for comparison. 
MEASUREMENTS : 
The Cranium. 
mm 
Length of nasals from base of horns, . i : : 114 
Breadth of nasals anteriorly, . 123 
Breadth of nasals at point of greiti easttletion in fnit 
of horns, . 112 
Distance between top of hosi at {dale of shies ipite : 151 
Transverse diameter of horns at a point midway between 
base and summit, 40 
Antero-posterior diameter of Horis at a point midway be 
tween base and summit, é i 66 
Length of diastema, sS: N 3 eae oe 3T 
