72 TITANOTHERIUM. 



Fam. 2. — Liparidigitata Ordinaria. 



TITAWOTHERIUlfl, Leidt. 



Titanotheriiim Prontii, Leidy. 



(Plate XVI. XVII., Figs. 1-10.) 



Falaeotlicrium, Prout: Am. Journ. Sci. Arts, 1847, iii., 248, figs. 1, 2. 



Palaeollierium ? Proutii, Owen, Norwood, and Evans: Proc. Acad. Nat. Sci., 1850, v., 66; Leidy: lb., 122; 

 Owen's Rep. of a Geol. Surv. of Wise, etc., 551. 

 lihinoccros Americamts? Leidy: lb., 1852, vi., 2. 



In the American Journal of Science and Arts for 1847, page 248, Dr. Hiram A. 

 Prout, of St. Louis, described and figured the fragment of a lower jaw containing 

 the true molars of a huge animal, supposed to be a species of Palfvotherium. 



The specimen, which was the first fossil from the eocene cemetery of Nebraska, 

 presented to the notice of the world, with another corresponding of the opposite 

 side, apparently from the same individual, were kindly loaned to me by Dr. Prout 

 for examination. (PL XVI. Fig. 1.) 



These strongly resemble the corresponding portion of the lower jaw of Palceo- 

 therium, and if they do not belong to this genus they do to one closely allied to it; 

 and if the animal preserved the same relations of size as Palaeotherium magnum it 

 was more than twice the size of this, which Cuvier has estimated to have been 

 over four and a half feet in height at the withers, or equal to the Bhinoceros of 

 Java ; less lofty than a large Horse, but stouter, with a more massive head, and 

 with extremities thicker and shorter. 



The two fragments of the lower jaw, before assuming their present mineralized 

 condition, were very much fractured, and the fissures are now filled up by a hard 

 matrix, which also adheres to their exterior surface in a concretionary form. 



Along the true molar series the jaw measures eleven inches; below the middle 

 lobe of the last molar it is six inches in depth ; and midway below the position of 

 the first true molar is nearly two and a half inches in thickness. The sides are 

 slightly convex vertically, and the bone is thick and rounded, and descends from 

 the position of the last molar towards the posterior broken margin of the specimen. 

 Two inches back of the last molar the depth of the fragment is nine and a half 

 inches, but its thickness is not so great as it is anteriorly. 



The inferior true molars are constructed upon the pattern of those of Palaeotlie- 

 rium; the anterior pair being composed of two, the last of three demiconoidal 

 lobes. These have crescentic summits, the extremities of which rise to the inner 

 side of the teeth, and there become confluent, and form prominent points. In the 

 specimens under examination, the outer side of the lobes of the molars is embraced 

 by a strong basal cingulum about two lines in depth. The inner surface of the 

 teeth forms a vertical plane, which is slightly convex antero-posteriorly, and does 

 not possess the slightest trace of a basal ridge such as exists in the true 

 PahieoihcrUiw. 



