306 
PEOBOSCIDEA. 
Measurements. 
M. 
Length of the base of the premolars..... 0,0002 
Length of the anterior lobe of the sectorial.... 0.0027 
Elevation of the crown of the third premolar. 0.0020 
Depth of the ramus at the third premolar... 0.0027 
Width of the ramus at the third premolar... 0.0020 
This species is provisionally referred to Putorius {Mustela, auct.) on 
account of the empirical character of the absence of posterior lobes of the 
third jiremolar, which is present in the type of Mustela {Maries, Cuv.). 
The reference is not final, because the specimen does not display the pos¬ 
terior part of the crown, the inner tubercle, nor the tubercular molar. It is 
less than half the size of the Mustela j)arviloba, Cope {Maries mustelinus, 
Cope), of the Loup Fork beds of Eastern Colorado 
PROBOSCIDEA. 
MASTODON, Cuvier. 
Mastodon, sect. Trilophodon, Falconer, Quart. Journ. Gcol. Soc. London, April, 1857. 
Tetracaulodon, Godman. 
Mastodon productus, Cope. 
Plates Ixx, Ixxi, and Ixxii. 
Proc. Acad. Phila., 1874, p. 221; Ann. Eept. Chief of Engineers, 1875, ii, p. 992. 
This Proboscidian is represented in the collections of the Survey by 
portions of a number of individuals. The specimen on which the first deter¬ 
mination was based is a mandible, which lacks only the coronoid processes 
and angles from both sides. Its symphysis is entire, containing two tusks. 
Each ramus supports two teeth, the fifth and sixth molars, which are more 
or less injured; the sixth of the left side being nearly perfect. A second 
and young individual is represented by the nearly'complete dentition of 
the maxillary bones at the time of its death, viz, three jiremolars (the first 
wanting from one side), and the first true molar of both sides, not quite 
protruded. A third and a fourth specimen include three-crested third 
molars; a fifth is a fourth or fifth three-crested molar, much worn, and the 
sixth and seventh are inferior sixth molars, one of them nearly perfect. In 
addition, there are bones of different individuals from many regions of the 
skeleton, but nothing approaching completeness. 
