620 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 59. 



possibly of the same one shown in figure 2 of plate 124. The double 

 inlet at the head of the valley is unusual. 



In the part of the collection from this place made by Mr. Barnum 

 Brown for the American Museum of Natural History is an upper 

 right third molar (plate 124, fig. 2). It is worn down to 25 mm. from 

 the root. The length is 36 mm. along the outer face; the width is 

 30 mm. The fossettes are wide and the enamel simple. There is 

 an inlet at the head of the postprotoconal valley. The catalogue 

 number is 14361. It is referred to the larger of the two horses found 

 at Anita. 



Among the bones referred with reservations to this species are 

 most of those of the left tarsus (Cat. No. 10138) in their natural 

 relations — a condition that shows that these parts were held together 

 by their ligaments when they reached the fissure. All of the bones 

 of this tarsus are present, except the consolidated internal and mid- 

 dle cuneiforms. As illustrating the size of these parts, the distance 

 from the rear of the calcaneum to the front of the external cuneiform, 

 161 mm., may be compared with that of the horse of medium size 

 already mentioned. This comparison shows that in case all other 

 parts were proportionately large, the extinct species was fully one- 

 fifth higher than the recent one. 



The following measurements are given of some of the individual 

 bones of these tarsi. 



Measurements of tarsal bones. 



Calcaneum, greatest length 



Calcaneum, greatest width across the tentaculum 



Calcaneum, height at middle of talus 



Astragalus, length on inner face 



Navicular, width 



Ectocuneiform, width 



No. 



174960, 



U.S.N.M. 



117 

 50 

 43 

 64 

 56 

 50 



In the collection is about the upper half of a right third meta- 

 tarsal (Cat. No. 10139). Unfortunately, the upper end is damaged 

 so that the side-to-side diameter can not be determined. The fore- 

 and-aft diameter is 50 mm.; in the recent horse, 44 mm. At a dis- 

 tance of 90 mm. below the upper end the side-to-side diameter of the 

 shaft is 40 mm.; the fore-and-aft, 35 mm. In the recent horse at 

 hand these diameters are respectively 32 mm. and 33 mm. There 

 are present two distal ends of third metapodials (Cat. No. 10140) ; 

 but the writer can not convince himself that either of them belonged 

 to the hinder limb. Three splint bones are in the collection (Cat. 

 No. 10141), with the distal ends missing. The diameters of the upper 

 ends are about one-third greater than in the recent horse used for 



