Douglass : Fossil Horses. 271 



found by the writer in the Upper White River beds of White Butte in 

 North Dakota. Though they differ somewhat from the type of Meso- 

 hippus brachystylus as described by Osborn, I refer them with doubt to 

 this species. No. 16390 and 1639^ are two upper molars, 1641 an 

 upper molar, and 1643 a l ast lower molar. 



Measurements. — Specimen No. 16390, apparently a first molar 

 (Plate LXV, figs. 5 and 6), has the antero-posterior diameter of crown 

 13 mm., transverse diameter 16.5 mm., height of protocone (slightly 

 worn) 5 mm., height of paracone 6 mm. 



The most prominent characteristics of these teeth are the following : 

 (1) crowns low, cross-crests especially so ; (2) parastyle fairly large 

 and connected with the anterior cingulum, but not with the outer 

 angle or point of the protoconule; (3) protoconule and metaconule 

 well developed and of nearly equal form and size ; (4) hypostyle well 

 developed, tending near apex to separate from the portion of the 

 cingulum external to it; (5) inner cingulum rudimentary; (6) outer 

 median ribs on crescents not prominent; (7) form of tooth nearly 

 quadrate. 



No. 1 64 1 is an upper molar. The antero-posterior diameter of the 

 crown is 13 mm. and the transverse diameter 16 mm. It differs from 

 the teeth just described in having a shorter inner antero-posterior di- 

 ameter, making the tooth less quadrate. 



No. 1643 * s a l ast ^ft lower molar. The antero-posterior diameter 

 is 20 mm. and the transverse diameter 10 mm. The metastylid is not 

 separated from the metaconid, but a faint external groove indicates a 

 beginning of this separation. 



Miocene Deposits. 

 Altippus taxus gen. et sp. nov. 

 (Plate LXVII, figs. 3 and 4 ; Plate LXVIII, figs. 6-8.) 

 (Type No. 836, Carnegie Museum Catalogue of Vertebrate Fossils.) 

 The type, which was found by the writer near the little railroad sta- 

 tion of Woodin on Divide Creek, about six miles south of the conti- 

 nental divide, in Silver Bow County, Montana, consists of parts of a 

 skull, the greater portion of a mandible, a radius, portions of two 

 femora, a tibia, a nearly complete hind foot, other bones of toes, and 

 numerous fragments. The only associated fossils were part of a skull 

 of Entoptychus Cope and parts of upper and lower jaws which are not 



