1917] 



Stock: Skull Structure of Mylodont Sloths 



173 



ever, that in the great series at Los Angeles there is no indication of 

 a fourth inferior tooth having exactly the same development as in 

 Brown's specimen. 



It appears undesirable to interpret the characters, given as diag- 

 nostic of the subspecies, as of sex value on account of the obvious 

 difficulty of explaining the apparent preponderance of one of the 

 sexes. 



The slender skulls, represented by nos. 642, 643, and 646, as 

 contrasted with a typical broad skull of M. harlani, may be compar- 

 able to dolichocephalic and bracbycephalic types in other groups of 

 animals. 



Measurements of Skull 



Cranium 



Length from anterior end of 

 maxillaries to posterior end of 

 occipital eonyles 



Length of palate from anterior 

 end of maxillaries to post- 

 palatine notch 



Greatest width of maxillaries, 

 measured across palate anter- 

 ior to first teeth 



Least width of palate posterior 

 to fifth tooth 



Least distance across ventral 

 margin of pterygoid plates 



Greatest width of muzzle 



Least width behind postorbital 

 processes 



Mastoid width above stylohyal 

 processes 



Greatest width across occipital 

 condyles 



Height, measured from plane of 

 basioccipital to dorsal plane .... 



Least distance from fifth super- 

 ior tooth to middle of post- 

 palatine notch 



Mandible 



Greatest length of symphysis .... 



Greatest predental widtli 



Depth of ramus between third 

 and fourth inferior teeth, 

 measured normal to inferior 



margin 



a, approximate. 



o 



Is J 



a> . 

 -~ o o 

 . -* J2 



fi to S3 

 ■OS 



fuaft 



'3 Km 

 c . 



°" to o 



n92.7 

 98. 



a,33. 



495. mm. 



486.4 



471.5 



fl.459.4 



«492.8 



219. 



217.6 



213.2 





0216.3 



136.4 



ol38.6 







125.4 



52.7 



57.4 

 111.7 



«55.5 





67. 



133.5 



(il35. 





al31. 



al31. 



94.6 



97.7 



91.7 



rtlOO. 



108. 



184.5 



al84. 



178. 



al67.7 



184.5 



131. 



132. 



118.5 



0.122.8 



128.2 



134.8 



«131.8 



129.6 



128. 



138.2 



45.6 



47.3 



50.8 





53.4 



