98 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 58. 



tance from the outer anterior style to the inner face of the anterior 

 fossette is 15 mm.; in the domestic horse mentioned it is 12 mm. 

 The greatest width may have been, therefore, 30 mm. or more. The 

 protocone is 11 mm. wide. The valley behind it has no reentrant 

 loop. The anterior fossette is 23 mm. long and differs much from 

 the usual form. There is no reentrant fold opposite the head of the 

 postprotoconal valley. The enamel at the front of the fossette is 

 much folded. Judging from the tooth at hand, one may conclude 

 that the horse here described may have had linear dimensions about 

 one- fourth greater than our large domestic horses, but it may have 

 been actually not so much larger. Equus compUcatus had the second 

 premolar but little larger than that given above for E. cahallus. 



Family TAYASSUIDAE. 



MYLOHYUS NASUTUS Leidy. 



Plate 4, figs. 2-3. 



From Cavetown there come two nearly complete, little worn, lower 

 left canine teeth, which are referred provisionally to this species 

 (pi. 4, figs. 2, 3). The total length of the smaller of these two 

 teeth (Cat. No. 9165), taken along the front border, is 80 mm.; but 

 a little of the tip of the root is missing. The crown (pi. 4, fig. 2), 

 similarly measured, is 26 mm. high. At the base the crown measures 

 fore and aft 10.3 mm. ; from side to side, 8 mm. The iimer and outer 

 faces are convex, the outer more strongly so. The anterior border 

 is rather obtuse, except near the summit of the crown. The hinder 

 border has a rather acute ridge descending from the summit, but just 

 outside of this there is a shallow groove. As a whole the hinder face 

 is quite different from that of the other peccaries observed. Each 

 lateral face is furnished with about four grooves. The one nearest 

 the front border, on the inner face, is broader than the others. The 

 hinder face is slightly worn in its distal half. A view of the outer 

 face of the tooth is presented. 



The larger of the teeth (Cat. No. 9166) measures along the front 

 border 93 mm., of which 45 mm. belongs to the crown (pi. 4, fig. 3). 

 The greater diameter at the base of the crown is 11.5 mm.; the 

 smaller, 9 mm. This tooth does not differ from the other in any im- 

 portant respects. 



MYLOHYUS EXORTIVUS Gidley. 



Pliite 4, figs. 4-13. 

 Tins species has been described by Gidley.' It is based on a series 

 of upper molars and preniolars (lacking pm-) of the right side, 

 and a lower jaw bearing all of the teeth, including incisors and ca- 

 nines (Cat. No. 8876). These were found in the cave near Corrigan- 



1 Proc. U. S. Nat. Mus., vol. 57, p. 676, text figs. 11-13. 



