78 PALAEOTHERIUM. 



The antero-posterior diameter of the tooth to which this fragment belonged, is 

 one inch ten and a half lines. The specimen still retains a portion of the internal 

 basal cingulum, extending anteriorly and posteriorly, and also portions of the two 

 enamel pits with the intervening antero-posterior valley of the tooth. 



The other fragment of a premolar, alluded to, consists of the fangs and a portion 

 of the outer lobes, which exhibits the same peculiarities as those already described. 



Dr. Evans states, in the report of Dr. Owen, previously quoted, that the remains 

 of the Palaeotherium [Titanother'mm) Proutii were found in a green, argillo-calcareous, 

 indurated stratum, situated within ten feet of the base of the geological section. 

 (See page 13 of this memoir.) He observes : "A jaw of this species was found, 

 measuring, as it lay in its matrix, five feet along the range of the teeth, but in such 

 a friable condition that only a portion of it could be dislodged; and this, notwith- 

 standing all the precautions used in packing and transportation, fell to pieces." 



" A neauly entire skeleton of the same animal was discovered in a similar posi- 

 tion, which measured, as it lay imbedded, eighteen feet in length, and nine feet in 

 height." 



The specific name applied to the animal whose remains have just been described, 

 was proposed in a letter to the Academy of Natural Sciences, of Philadelphia, by 

 Drs. Owen, Norwood, and Evans, in honor of Dr. Hiram A. Prout, of St. Louis, 

 who first indicated its existence. 



PALAEOTOERIUiTI, Cuvier 

 Palacotlieriiiiii g^igauteuiu, Leidy. 



(Plate XVII., Figs. 11-13.) 



In the collections of Messrs. Culbertson and Dr. Owen, there are several frag- 

 ments of molar teeth of an animal equally huge with the T itanotherimn, and most 

 probably belonging to a species of Pulueutherimn, which was twice the size of the 

 Palaeotherium maijnum. 



The fragments, of which there are five, are only single external lobes of the 

 upper molars. These, externally, correspond to the description of Cuvier of the 

 teeth of Palaeotherium. A conjoined pair of the lobes forming the outer part of a 

 tooth, "present the external face strongly inclined inwards in descending, and divided 

 by three salient ridges into two concavities, which are rounded towards the fangs, and 

 terminate in a triangular cusp at the masticating surface, the basal angles of which 

 rest upon the termination of the salient ridges." The median ridge is a thick 

 obtuse fold outwards of the tooth, and the anterior and posterior ridges are acute, 

 roughened offsets from the basal ridge, descending to the masticating surface. 



The measurements of the more perfect specimens are as follows : — 



Inclics. Lines. 

 Length of the longest lobe ......... 2 4 



Length of a second specimen ......... 2 



Breadth of the second specimen at the basal angles of the cusp ... 1 8 



Length of the shortest lobe ......... 1 7 



Breadth of the shortest lobe at the basal angles of the cusp .... 1 3 



