224 



mm. 



9 





42 





32 





31 





5 





30 





31 





40 TRANS. OF THE WAGNER FREE INSTITUTE OF SCIENCE. 



Length of maxilla from behind the fifth molar alveolus to the 

 premaxillary articulation, ...... 



Fore and aft diameter of first premolar, .... 



second " 



third " .... 



fourth " 



Transverse diameter of first premolar, .... 



second " 



" " third and fourth premolar, 



In a collection of fossils from Northern Nicaragua submitted to the in- 

 spection of the author by Mrs. Dr. B. F. Guerrero, and forming the subjects 

 of a notice in the Proceedings of the Academy of Natu- 

 ral Sciences, 1886, page 275, were two molar teeth of 

 the Horse in association with remains of Elephant, 

 Mastodon, Megatherium, Ox, Toxodon burmeisteri and 

 Hydrochoerus robustus. The teeth of the Horse, most 

 probably of an indigenous species, are not distinguish- 

 able from those of the Domestic Horse, and most likely 

 pertain to the South American extinct species dis- 

 tinguished by Prof Owen with the name of Eqints air- 

 videns. One of the specimens, of which a view of the 

 triturating surface is given in the upper subjoined cut, 

 is 65 mm. long at its outer fore part and has a breadth 

 of 26.5 mm. The other specimen, considerably more 

 worn, has the crown at the outer fore part 40 mm. 

 long, and the triturating surface, represented in the 

 annexed cut is 23 mm. fore and aft and 27 mm. transversely. 



