1913] Stock: Nothrotherium and Megalonyx 349 



The foramen magnum is moderately large and subeircular in 

 outline. The superior margin is notched at the middle. In 

 N. escrivanense this border is entire. The occipital condyles are 

 similar to those of the Brazilian species, having their larger 

 articular face directed outward and forward. 



Figs. 6, 7, and 8. Nothrotherium graciliccps, n. sp. Bight second 

 superior tooth, no. 10485, X %. Rancho La Brea Beds. Fig. 6, view of 

 triturating surface; fig. 7, posterior view; fig. 8, lateral view. 



Dentition. — A single tooth, no. 10485 (figs. 6, 7, and 8) corre- 

 sponds in section to the second alveolns of the right side. It 

 differs from a similar tooth (no. 8702) of Nothrotherium 

 sliastense from the Potter Creek Cave in lacking the cnrvature 

 of the inner face. Its anterior face is longitudinally concave 

 and broadly convex transversely. The posterior face is slightly 

 concave transversely, and the lateral faces are furrowed. The 

 triturating surface is deeply troughed transversely, especially 

 toward the inner side. 



Measurements op Skull and Dentition 

 Length of skull, anterior end of palate to posterior end of 



occipital condyles 300. mm. 



Length of palate, anterior end to post-palatine notch 131. 



Width of palate between second alveoli 22.9 



Greatest width of muzzle 71. 



Greatest width above orbits 102. 



Least width behind orbits 77.2 



Mastoid width above the stylohyal processes 112.6 



Vertical height of occiput from plane of basioccipital to lamb- 



doidal suture 83. 



Length of dental series, from anterior wall of first alveolus to 



posterior wall of last alveolus 57.5 



M-, no. 10485, anteroposterior diameter at triturating surface.. 13. 

 M-, no. 10485, transverse diameter at triturating surface 10. 



