434 University of California Publications in Geology [Vol. 7 



The relationships of the interesting form from Mohave seem 

 almost to require the establishment of a distinct group to give 

 to this species such a position in the classification as will clearly 

 indicate its true affinities. It could be assigned tentatively to a 

 place with Archaeohippus, as an advanced stage with protoconule 

 and hypostyle more progressive, eingulum of the protoeone side 

 absent, and complication of the metaloph not more advanced. 

 It could be referred to Parahippus, as a primitive stage with 

 crochet undeveloped, though the metaloph shows secondary fold- 

 ing, and with metaconid and metastylid in beginning separation. 

 The reference of this form to one of the described genera depends 

 somewhat upon the extent to which the limits of these groups 

 may be expanded by later studies. A reference to Parahippus 

 is apparently open to fewer definite objections than a reference to 

 Archaeohippus. 



Transmitted October 13, 1913. 



