No. 2391. DESCRIPTIONS OP PLEISTOCENE VERTEBRATA—HAY. 619 



The second right premolar is a nearly unworn tooth. In order 

 to get an adequate view of the enamel, the tooth was sawn across, 

 about 1 inch below the grinding surface. The end of the proximal 

 section was polished and a view of it is presented (pi. 118, fig. 11); 

 but this is the reverse of the one that would be shown on the grinding 

 surface of a tooth of that side. The upper right hindermost molar 

 is worn down to about 45 mm. of the root. The length of the crown 

 along the outer border is 33 mm.; the width is 24 mm.; the fore-and- 

 aft diameter of the protocone, 17 mm. Besides the unusual length 

 of the protocone it is thin and flat, differing in these respects greatly 

 from that of the tooth figured by Gidley. 10 The postprotoconal 

 valley, too, has a deep inlet near its head. The width and thinness 

 of the protocone is shown in two fragments of upper teeth. The 

 hindermost lower molar had just begun to wear. The height is 85 

 mm.; the length at half of the height, 38 mm.; the thickness in 

 front, 15 mm. A fragment of an upper tooth (Cat. No. 10215), 

 somewhat worn, is 80 mm. high and considerably curved. A frag- 

 ment of a little-worn lower tooth (Cat. No. 10216) is 100 mm. high. 

 A little-worn and deeply cupped incisor (Cat. No. 10217) is 20 mm. 

 wide. It appears to be safe to refer these teeth to Equus occidentalis. 

 There are in the collection a few vertebrae and fragments of other 

 bones of Equus, some of which may belong to this species. It is not 

 at all improbable that the remains here described will prove eventually 

 to belong to an undescribed species. 



EQUUS GIGANTEUS? Gidley. 



Plate 118, fig. 12; plate 124, fig. 2-3. 



The larger horse of the collection is referred with doubt to Mr. 

 J. W. Gidley's Equus giganteus " found in southwestern Texas and 

 based on a tooth which had been referred by Cope 12 to E. crenidens. 

 The reason for this identification of the Anita materials is admitted 

 by the writer to be the evident large size of the horse. There are 

 present an upper right hindermost molar (Cat. No. 14361 Amer. 

 Mus. Nat. Hist.) and some fragments of teeth which appear not to 

 belong to Equus occidentalis; but these fragments (Cat. No. 10137) 

 present no special resemblance to the tooth which forms the type of 

 E. giganteus. Two of the fragments are here illustrated. Figure 12 

 of plate 118 presents a part of the anterior fossette of an upper grind- 

 ing tooth. The section shown belongs about an inch above the root 

 of the tooth. The distance across this fossette is 16.2 mm.; in a large 

 domestic horse the corresponding distance is 15 mm. Figure 3 of 

 plate 124 gives a view of the postprotoconal valley of an upper tooth, 



io Bull. Amer. Mus. Nat. Hist., vol. 14, p. 115, fig. 10. 



» Idem, p. 137, fig. 27. 



13 Amer. Naturalist, vol. 19, p. 1208, pi. 37, fig. 4. 



