174 University of California Publications in Geology [Vol. 10 



Measurements of Dentition 



< < K < < 



a. Kf q a, Km g Mm wm 



** N o o ^if) o T! ** o 



.f£ . w O)J3 S-s'.a 



•Ort • C a! ,_jdc3 ■ O cj 



M-, anteroposterior diameter a?33.5 mm o31.8 



M5, transverse diameter a'18.3 20. 



M 2 , anteroposterior diameter a28.6 a23.2 28.3 



M 2 , transverse diameter o24.3 o20.3 23. 



M 1 , anteroposterior diameter 22. a22.4 



M 1 , transverse diameter 23.3 23.7 



M5, anteroposterior diameter o27.3 22.3 25.6 



M-, transverse diameter o20. 18. 22.4 



Length of superior series, from anterior end 

 of first alveolus to posterior end of fifth 



alveolus 146.5 al37. 



Length of superior series, from anterior end 

 of second aveolus to posterior end of fifth 



alveolus 119.6 110.8 120.6 



Mj, anteroposterior diameter al4.5 



Mj, transverse diameter al5.4 



Mj, anteroposterior diameter 25.7 



M;, transverse diameter 20.2 



M5, diameter of occlusal surface normal to 



greatest diameter 17. 



Mj, anteroposterior diameter 52. 



Mj, greatest diameter of anterior lobe «28.7 



Mj, greatest diameter of posterior lobe al9.7 



Length of inferior series, alveolar measure- 

 ment 130.4 



a, approximate. al, alveolar measurement. 



CONCLUSIONS 



The following additional facts have been noted with reference to 

 the rnylodont skull series from Rancho La Brea : 



Three, possibly four, crania contained in the Museum of History, 

 Science and Art of Los Angeles, are recognized as representing a form 

 subspecifically distinct from typical Mylodon Aiarlani. 



These crania differ from M. harlani of Rancho La Brea in exhibit- 

 ing in combination a rather narrow brain-case with a narrow palate 

 posterior to the fifth tooth. 



The Nebraska skull described by Brown can not be referred to 

 the new subspecies from Rancho La Brea, since its characters, although 

 in certain respects approaching those of the latter, are still quite 

 distinct. The Nebraska specimen presumably represents Mylodon 

 harlani, but may belong in a subspecies distinct from the two known 

 to occur at Rancho La Brea. 



Transmitted December 23, 1916. 



