UNIVERSITY OF CALIFORNIA PUBLICATIONS 



BULLETIN OF THE DEPARTMENT OF 



GEOLOGY 



Vol. 10, No. 16, pp. 267-286, 10 text figures Issued May 11, 1917 



STRUCTURE OF THE PES IN MYLODCW ^ < 

 HARLANI 



BY 



CHESTEK STOCK 



CONTENTS 



PAGE 



Introduction 267 



Structure of pes 268 



Comparison with other mylodont genera 278 



Comparison with Lestodon 279 



Comparison with Scelidotherium 280 



Modification and specialization of pes 282 



Eelation of mylodont pes to supposed human footprints in Pleistocene strata 



at Carson City, Nevada 284 



Conclusions 285 



Introduction 



It is more than seventy years since the great British comparative 

 anatomist, Richard Owen, 1 described the skeleton of Mylodon robustus 

 from remains obtained in the Pampean Pleistocene of South America. 

 In this masterpiece of exact observation and deduction there is included 

 a discussion of the nearly complete manus and pes as they occur in that 

 species. The figures 2 of M. robustus are by far the best available, 

 illustrating the skeletal structure of the feet in the genus, and have 

 been widely used as a basis for comparison with other mylodont 

 material. 



Since the publication of Owen's memoir, information concerning 

 the mylodont sloths from the North American Pleistocene has grad- 



1 Owen, R., Description of the skeleton of an extinct gigantic sloth, Mylodon 

 robustus, Owen, with observations on the osteology, natural affinities, and prob- 

 able habits of the megatherioid quadrupeds in general, London, 4to., 176 pp., 

 24 pis., 1842. 



2 Ibid., pis. 15 and 21 (see also pis. 16 and 22), 1842. 



