1877.] 585 [Cope. 
Hlevation of external cusp......-...-sceee cece eee eee 065 
= internal “ ..... sarees ae ued gtuisiaiareea! else Ss 035 
Length between apices of external cusps..............- 043 
The molar tooth described exceeds in transverse dimensions that of the 
Mastodon ohioticus, and evidently belonged to one of the most colossal of 
land animals. Its generic position is near to Mastodon and Dinotherium, but 
if the tooth on which my observations are based be complete, it is distinct 
from either. The possession of only two transverse crests separates it 
from the former, and would, were the tooth an anterior molar, refer it to 
the latter. As it appears to be a posterior molar, this view of its affinity 
becomes untenable, and I therefore establish for it a new genus, under the 
name CHNOBASILEUS. The tooth described resembles that of the genus 
Taptrus, but differs in the absence of the external trihedral enlargement 
of the cross crests seen in the superior molars of the former, and also in> 
the tubercular and fissured character of the crests proper. The species 
may be called C. tremontigerus. 
The typical specimen was probably obtained in Texas, but I am not yet 
informed as to the precise locality. 
IssuED Marca 19, 1877. 
