SCIUROMORPHA. 817 



masseteric fossa is a prominent edge, which descends below the inner infe- 

 rior margin of the ramus. The molars diminish regularly in size forwards. 

 Their crowns are basin-shaped, with the anterior angle of the external 

 border elevated, and the inner border notched medially. Incisor com- 

 pressed. 



Length of inferior molar series, .010; anteroposterior diameter of first 

 molar, .0024; length of fourth molar, .003; depth of ramus at diastema, 

 .OOr.S; depth at third molar, .0095. 



This species is considerably larger than the S. relictus. It is dedicated 

 to Jacob L. Wortman, of Eugene, Oregon, who found the typical speci- 

 men in the John Day Miocene deposit of that State. 



SciURUS RELICTUS. 



Annual Report U. S. Geol. Surv. Terrs., 1873 (1874), p. 475. Paramys rtlictug Cope; Synopsis New Ver- 



tebrata Colorado, October, 1875, p. 3. 



Plate LXV ; fig. 35. 



This species was established on two mandibular rami, with all the teeth 

 complete. It was referred to the genus Paramys, because I found no differ- 

 ence between the corresponding parts of the respective species; but as the 

 characters of the latter are chiefly observable in the maxillary teeth, the 

 reference was not final. 



The ramus is quite robust, and has the general proportions of that of 

 S. hudsonius. The diastema is much shorter than the tooth-line, and the 

 foramen mentale is situated below its middle, a little above half way betweea 

 the inferior and superior borders of the ramus. The masseteric fossa has an 

 angular termination below the posterior border of the second molar. The 

 ascending ramus begins opposite the posterior border of the third molar. 

 The symphysis is not abruptly recurved, but commences in a gentle ascent 

 of the inferior border to the incisive alveolus. The latter issues lower down 

 than in the species of Eumys and Hdiscomys described in this volume. 



The inferior incisor tooth is less curved than in the species of the 

 genera above named, and is not so much compressed. Its section is sub- 

 triangular, with the anteroposterior diameter a little greater than the trans- 

 verse in front. The anterior face is gently and equally convex in trans- 

 52 c 



