UNIVERSITY OF CALIFORNIA PUBLICATIONS 



BULLETIN OF THE DEPARTMENT OF 



GEOLOGY 



Vol. 8, No. 18, pp. 319-334, 6 text-figures Issued December 5, 1914 



SKULL AND DENTITION OF THE MYLODONT 

 SLOTHS OF RANOHO LA BREA 



BY 



CHESTER STOCK 



CONTENTS 



PAGE 



Introduction 319 



Cranium 322 



Mandible .• 325 



Dentition 327 



Specific Comparison with Other Mylodont Forms 330 



Conclusions 334 



INTRODUCTION 



Three generally recognized species of mylodont sloths have been 

 described from the North American Pleistocene on the basis of skull 

 and dental characters. The genotype, Mylodon harlani, was determined 

 by Owen 1 on a fragmentary lower jaw from Big Bone Lick, Kentucky. 

 Paramylodon nchrascensis Brown and M. garmani Allen are based 

 on skulls with associated skeletal material from Pleistocene beds near 

 Hay Springs, Nebraska.- A superior series of teeth of M. harlani 

 was described by Cope 3 from Petite Anse, Louisiana. Prom the same 



i Owen, R,, The Zoology of the Voyage of H. M. S. Beagle, etc., Part 1, 

 Fossil Mammalia, p. 68, pi. 17, figs. 3 and 4, 1840. 



- Brown, B., A New Genus of Ground Sloth from the Pleistocene of Nebraska, 

 Bull. Amer. Mus. Nat. Hist., vol. 29, pp. 569-583, pis. 50-51, 1903. 



Allen, G. M., A New Mylodon, Mem. Mus. Comp. Zool. Harv. Coll., vol. 40, 

 pp. 319-346, 4 pis., 1913. 



3 Cope, E. D., On Some Plistocene Mammalia from Petite Anse, La., Proc. 

 Amer. Philos. Soc, vol. 34, pp. 458-468, pis. 10-12, 1896. 



