Texas, and prosoiited hy him to llic Academy of Philadelphia. In the eom- 

 plexity of lijlding oi" the enamel, as seen on the triturating surl'aee, this looih 

 is quite characteristic of Eguus comjdicatus. 



Fig. 12 represents a first lower temporary molar, one of tlie 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, i§ 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 shai'k-teetli, remains of mastodon, elephant, &c. 

 Many of them are undistinguishable 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 compUcatus. 



Figs.' 16 and 17 re|)resent 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 surfece of the upper molar, would 

 probably indicate that they belong to Equus conqdicatus. 



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

 to E. compllcatits, are as follows : 



First upper molar, Figs. 3, -1.— Leugtli of crown externally, 35 lines ; antero-posterior 

 diameter. 21 Hues; transverse diameter, 15 lines. 



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

 21 Hues; transverse diameter, 15J lines. . 



Lust upper molar, Figs. 1, 8.— Leugtli at antero-extermil border from end of fang, 3G 

 lines; length posteriorly ,,19 lines; breadth of triturating surface, 10 lines; width, 21 

 lines. 



Last lower molar. Fig. 0.— Breadth, 10.^ lines; width, 7 lines. 



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

 width, 73 lines. 



U2)per second or third molar, Fig. 11.— Length of crown, 32 lines; breadth, 11 lines; 

 width, 15 lines. 



First lower temporary molar, Fig. 12.— Breadth, 174 lines; width, 8 lines. 



