AET. 35 MASTODO]SrS FOUND IN TEXAS HAY 7 



the crown. The tooth of the right side is very similar to the left 

 one, but it is slightly smaller, the length being 26 mm,, the width 

 19 mm. 



The roots of these teeth had evidently attained considerable size 

 but both are broken off where they joined the crowns. In the base 

 of each crown is a pulp cavity 11 mm. long and 6 mm. wide; and this 

 was continued into the root. The walls of the root were from 3 

 to 5 mm. thick. There appears to have been one fang in front and 

 a larger one behind. The fourth premolar, if there was one, is not 

 in the collection. It will be further mentioned under the description 

 of the fourth milk molar. A fourth premolar was present in Gom- 

 fJiotherium Jeptodon {Mastodon angustidens) . 



These teeth have the narrow oval form of the upper second pre- 

 molar described by Schlesinger ^^ but this is only 22 mm. long and 

 15.7 mm. wide. On the other hand, the Navasota teeth are consider- 

 ably shorter, and relatively much narrower than the upper third 

 premolar described by Schlesinger ;^2 and the structure is different. 

 Schlesinger gives the length as 39.4 mm., the width as 29 mm. It is 

 evident, however, that the Nuvasota animal was smaller than the one 

 in Schlesinger's hands, and the lower premolars are likely to be 

 narrower than the upper ones. 



The Navasota teeth differ from both the second and the third pre- 

 molars described by Schlesinger in having the two crests more sharply 

 separated by the transverse valle3^ Were it not that these premolars 

 have been found in place in the jaw^ (Schlesinger, as cited) one 

 might conclude that the left one belonged on the right side and 

 vice versa. The Navasota teeth appear to agree in structure with the 

 lower third premolar (designated as the first) of Gomphotheriura 

 leptodon described and figured by Lartet in 1859." This appears, 

 however, to have had a cingulum on the outer face. 



3. Description of the milk molars and true molars 



In the collection are the lower third milk molars, right and left. 

 The one of the left side is the most nearly complete, the crown being 

 wholly uninjured, but most of the hinder root and a part of the 

 front root are broken off. In the one of the right side the front 

 root is gone and with it a part of the first crest. The crown con- 

 sists of three crests and front and rear talons. The crests are 

 directed across the crown obliquely outward and backward. The 

 crown of the left tooth is 60 mm. long, 28 mm. wide at the first 

 crest, and 35 mm. at the third (pi. 4, figs. 1, 2). On the inner side 

 the second crest is 23 mm. high. The summits of the cones of all 



"Deakschr. Naturh. Staatsmus., Vienna, vol. 1, p. 14, pi. 2, fig. 3. 



" Idem, same page and plate, fig. 4. 



"Bull. Soc. Geol. France, ser. 2, vol. 16, p. 491, pi. 14, fig. 2, B. 



