Vol. 6] 



Merriam: Notes on Desmostylus. 



407 



the mouths of rivers; its known geographic distribution ex- 

 tended around the north Pacific from southern California to 

 Japan ; its geologic range in America is found in a zone near 

 the base of the Miocene. As the time equivalence of the for- 

 mations in which Desmostylus occurs is not yet fully understood, 

 later study may show that the downward limit of range corre- 

 sponds to the Oligocene or that the upper limit corresponds to 

 middle Miocene. 



DENTITION 



The teeth of Desmostijl its, as known from the Californian 

 specimens (figs, la to 2b), consist of several pairs of high pillars 



Figs, la and 16. Desmostylus, sp. M\ X Lower Miocene, north of 

 Coalinga (NW % see. 29, T. 18 S, R. 15 B). Collected by Robert Anderson. 

 Fig. la, lateral view; fig. lb, occlusal view. 



Figs. 2a and 2b. Desmostylus, sp. M w no. 9091, X V>. California, 

 exact locality unknown. Fig. 2a, lateral view; fig. 2b, occlusal view. 



