245 



Texas, and presented by him to the Academy of Philadelphia. In the com- 

 plexity of folding of the enamel, as seen on the triturating surface, this tooth 

 is quite characteristic of Equus complicatus. 



Fig. 12 represents a first lower temporary molar, one of the specimens from 

 the asphaltum-bed of Hardin County, Texas. 



Fig. 13 represents an upper last temporary molar, another of the specimens 

 from the locality just indicated. 



Fig. 14 represents an upper molar of Equus complicatus from the ''phos- 

 phate-beds" of Ashley River, South Carolina, 



Fig. 15 represents an inferior molar from the same locality. The upper 

 molar, in the complex condition of its enamel-folding, is characteristic of the 

 species. The lower molar presents nothing distinctive from those of the 

 recent horse. 



Teeth of horses are frequently found in the Ashley phosphate-beds, mingled 



with abundance of fossil shark-teeth, remains of mastodon, elephant, &c. 



Many of them are ^indistinguishable from those of the recent horse, but others 



in size and complexity of the enamel-folding in the superior molars are suffi- 



"ciently characteristic of Equus complicatus. 



Figs. 16 and 17 represent an upper and a lower molar, which were found 

 associated with remains of mastodon at Pittstown, on the banks of the Sus- 

 quehanna River, Luzerne County, Pennsylvania. The teeth are more than 

 half worn away. Their size, and a rather greater degree of complexity than 

 usual in the enamel lines of" the triturating surface of the upper molar, would 

 probably indicate that they belong to Equus complicatus. 



Measurements of the specimens, represented in Figs. 3 to 17, and referred 

 to E. complicatus, are as follows : 



First upper molar, Figs. 3, 4. — Length of crown externally, 35 lines ; anteroposterior 

 diameter, 21 lines; transverse diameter, 15 lines. 



First upper molar, Figs. 5, 0. — Length of crown, 33 lines ; autero-posterior diameter, 

 21 lines; transverse diameter, 15J lines. 



Last upper molar, Figs. 7, 8. — Length at autero-external border from end of fang, 30 

 lines; length posteriorly, 19 lines; breadth of triturating surface, 19 lines; width, 21 

 lines. 



Last lower molar, Fig. 9. — Breadth, 1G£ lines; width, 7 lines. 



Fourth or fifth lower molar, Fig. 10. — Length of crown, 34 lines; breadth, 13£ lines; 

 width, 7i|- lines. 



Upper second or third molar, Fig. 11. — Length of crown, 32 lines; breadth, 14 lines; 

 width, 15 lines. 



First lower temporary molar, Fig. 12; — Breadth, 17^ lines; width, 8 lines. 



