1917 



Stock: Skull and Dentition of Nothrotherium 



151 



Km 



Measurements of Mandible" ^ „ 



CtflJ 



e 



2 So 



, O cz 



Length from anterior end of sym- 

 physis to posterior end of condyle 275 mm. 



Distance from anterior end of sym- 

 physis to anterior border of 

 alveolus for M 5 100.9 



Distance from posterior border of 

 alveolus for Mj to posterior end 

 of angle 121.2 



Greatest length of symphysis 90.4 



Greatest depth between Mj and M3, 



measured normal to tooth-row.... 56.6 



Least height posterior to Mj 43 



Greatest height from angle to coro- 



noid process 106.6 



Height of condyle above ventral 



border of angular process 79.7 



Thickness of horizontal ramus at M3 27.2 



Distance between inner alveolar 

 borders of fourth cheek-teeth .... 33 



* Where association of mandible with cranium 

 separate number. 



t This mandible may belong to cranium 313. 

 a, approximate. 



M 00 o 

 ~ O J3 



30. 



w p 



■£ 00 o 

 J3 ■* a 



m i 

 Wffl 



w p 



tS® 2 



^ CO v 



. O « . O « . o « 



2; pi y y Pi y y, Pi 



((260. 



284.4 a267 



196.2 a96.8 104. 



1 09.3 



134.6 al20 124.3 117.1 

 90.3 ((82.9 90.2 87 



60.6 

 47.5 



121.4 



29.3 



54.2 

 42 



56.1 53 

 44.8 38.6 



all3.8 nlOl.7 



26.7 28.2 25.3 



24.3 



Us 



y.'ypi 



61.3 

 46.8 



; . 



1%S 



. o « 



y ypi 



61.6 

 47.5 



26.4 26.8 



is in doubt, the former is listed under 



DENTITION 



The dental formula in the Rancho La Brea Nothrotherium as in 



the Brazilian species is |-~| . In possessing a reduced dentition. 



Nothrotherium differs markedly from the certainly known Miocene 

 Megalonyehidae and Planopsidae as well as from the Pleistocene genera, 

 Megalonyx and Megatherium. All the teeth are considerably smaller 

 than in Megalonyx. The external layer of cement on the teeth may be 

 only as thick relatively as in Hapalops. 



Superior Series. — The tooth-rows extend very nearly parallel, the 

 palate increasing slightly in width between the fifth cheek-teeth. The 

 teeth are more closely spaced than in Miocene genera. In the Rancho 

 La Brea species the largest interspace occurs between the alveoli of 

 M- and M-. Reinhardt states that in the Brazilian species of Nothro- 

 therium the teeth are equally spaced. 



As in the various species of Santa Cruz ground-sloths the differ- 

 entiation of the superior molariform teeth into a small M-, much 



