UNIVERSITY OF CALIFORNIA PUBLICATIONS 



BULLETIN OF THE DEPARTMENT OF 



GEOLOGY 



Vol. 6, No. 18, pp. 403-412 Issued November 1, 1911 



NOTES ON THE GENUS DESMOSTYLUS 

 OF MARSH 



BY 



JOHN C. MERRIAM 

 CONTENTS 



PAGE 



Introduction 403 



Occurrence — 404 



Dentition 407 



Skeleton 410 



Systematic Position 412 



INTRODUCTION 

 The peculiar mammalian genus Desmostylus described by 

 Marsh 1 as a sirenian is of considerable interest to palaeontolo- 

 gists, as it represents a peculiar combination of proboscidean 

 and sirenian characters. It is, however, one of the most imper- 

 fectly known of the Pacific Coast vertebrate forms, the total 

 amount of American material available for study including only 

 a few teeth and some scattered fragments of skeletal elements. 

 Recent discoveries seem to show that Desmostylus may be a valu- 

 able horizon determiner in geologic work in California, and 

 may also have some importance in geological correlation between 

 America and Asia. It has, therefore, seemed desirable to bring 

 together all of the information available concerning this form, 

 in the hope that such a statement may assist in the accumulation 

 of further data relating to its structure and range. 



i Marsh, O. C, Am. Jour. Sc., vol. 35, pp. 94 to 96, 1888. 



