160 SYSTEMATIC PALEONTOLOGY 



their length but at the posterior end of a tooth the folds are much nearer 

 together on the grinding than on the root side, spreading out somewhat 

 like a fan or the leaves of a partly-opened book. This is well shown in 

 the plate giving side views of teeth of Elephas columbi and imperator, 

 and in such cases the measurements have been made and folds counted 

 near the middle of the tooth. 



Genus MAMMUT Blumenbach. 



Mammut amebic anum (Kerr) 



THE AMERICAN MASTODON. 



Plates XXXIV, XXXV, XXXVI. 



Elephas americanus Kerr, R., 1792. Anim. Kingdom, p. 116. 

 Mammut ohioticum Blumenbach, 1799. Naturgeschichte, Ed. vi, p. 698. 

 Mastodon americanus Cuvier, 1834. Recherches ossemens fossiles, p. 478, 



pi. xix, figs. 1-3. 

 Mastodon maximus Hall, 1843. Geol. of N. Y., p. 363, plate, fig. 74, text fig. 



173. 

 Mastodon giganteus Warren, J. C, 1852. The Mastodon Giganteus of N. A., 



pp. i-viii; 1-219, pi. 1-26 + 1. 

 Mastodon ohioticus Leidy, 1859. Holmes Post-Pi. Fossils of S. C., p. 108, 



pi. xix, figs. 1-3. 

 Mastodon giganteus Agassiz, 1862. Amer. Jour. Sci., ser. ii, vol. xxxiv, p. 



135. 

 Mastodon giganteus Cope and Wortman, 1884. 14th Rept. State Geol. Ind., 



pt. 2, p. 33, pi. iii, figs. 1, 2; pi. vi, fig. 1. 



Description. — The common, or American mastodon, Mammut ameri- 

 canum, is so well known as to require little description. It is readily 

 distinguished from all other American mastodons by the character of its 

 teeth which bear simple tent-shaped ridges and have the valleys between 

 unobstructed. Its nearest relative is M. borsoni from Eussia, and while 

 Mme. Pavlow 3 believes that teeth from Pestchna, Eussia, are those of 

 M. americanum, it will be best to consider this as open to doubt until 

 more conclusive evidence than that of a single, imperfect ramus of a jaw 

 is discovered. As a matter of fact, mastodon molars are so extremely 



3 It has not been thought necessary to give extended references to the 

 synonymy and bibliography of the species discussed as this has been so thor- 

 oughly done by Hay in his Bibliography and Catalogue of the Fossil Verte- 

 brata of North America. Bull. U. S. Geo. Survey, No. 179, 1902. 



