NO. 2147. TWO EXTINCT MAMMALfi FROM TEXAS— HAY. 121 



the others convex. The hinder faces of all are concave — that of the 

 fourth tooth most so of all. The inner faces are flat or slightly con- 

 vex — that of the fourth rather strongly so. The outer faces are some- 

 what concave, showing a shallow groove along their whole height. 

 All of these teeth have a height of about 50 mm. They are hollow 

 down to within about 10 mm. of the grinding surface. 



On the front end of each maxillar}^ there is a surface for the articu- 

 lation of the corresponding premaxilla. The two surfaces are sepa- 

 rated by a space of 20 mm., and each has a length of 30 mm. On the 

 lower side of the maxilla is another surface for a backwardly di- 

 rected process of the premaxilla. In case the premaxillae corre- 

 sponded in size to those of the Brazilian species mentioned above, 

 each had a length of about 30 mm. 



This is not the first discovery of the genus Nothrot/ierhimm'^orth. 

 America. In 1905 ^ Sinclair reported it, with some doubt, from Potter 

 Creek cave, Shasta Count}'', California, He had for description a 

 part of a lower jaw without teeth and fourteen loose molars. The 

 name N. shastense was given to the species. 



In order to determine the relationship of the Texan specimen to 

 that found in northern California, it is necessary to compare with 

 the teeth of the former those which Sinclair has represented by 

 figures 3, 5, and 8 of his plate 23. figures 3 and 5 must be second 

 and third teeth. Of the tooth- represented by his figure 3 both the 

 front and the rear faces are convex in section, whereas both the second 

 and the third teeth of N. texanum have the front face convex and the 

 rear face concave. Sinclair's figure 5 resembles somewhat the sec- 

 tion of the third tooth of the Texan species ; but here, as in the tooth 

 of his figure 3, the inner face of the tooth is more or less concave; 

 whereas, in the Texan animal, the inner face is flat. However, it is 

 in the hindermost tooth that the greatest difference is found. In 

 the California species the front of the tooth is convex, the rear flat. 

 In the Texan species the rear of the tooth is deeply concave. It 

 appears to be evident that two distinct species are indicated. 



In 1913,^ Stock described a skull, lacking the lower jaw and some 

 other parts, which he called N. graciUceps. The type is now in the 

 Los Angeles Museum of History, Science, and Art, where the writer 

 has had the privilege of examining it. This skull resembles closely 

 that from Texas in size and proportions, as may be seen from the 

 measurements given on page 117. There are, however, in the Texan 

 slmll, certain deviations from that of N. gradliceips which appear to 

 make it advisable to give to it a distinctive specific name. One can 

 not rely wholly on the differences which are seen in the two skulls 

 for additional specimens may be intermediate. 



iBull. Dept. Geol., Univ. Cal., vol. 4, p. 153, pi. 23. 

 = Idem, vol. 7, pp. 341-352, figs. 1-8. 



