224 PROCEEDINGS OF THE ACADEMY OF 



The lower series of three premolars and three molars has 

 rneasnrcd in its complete conrlition about 14 inches in length. 



The isolated canine tooth, which I supi)oseto have pertained to 

 the lower jaw, is a remarkable tooth, and has more of the usual 

 characters of an incisor tooth. The crown is sliort, conical, and 

 robust, and is bounded internalh' with a thick basal ridge. The 

 length of the crown in its present worn condition is 13 lines; its 

 width at base from witliout inwardly, about the same measurement, 

 and from side to side 11 lines. 



Of several imperfect thoracic vertebrre, one of the best preserved 

 has the bod}' over 2 inches long at the lower margin and about 3i 

 inches in breadth. The centre are strongly- concavo-convex. 



The head of a thigh-bone is about 4 inches in diameter, and has 

 a large deep pit on its inner side for a terete ligament. 



The distal end of a thigh-bone is 6 inches in transverse diameter, 

 and the trochlea for the patella Is over 3 inches wide. 



Accompanying the Titanotherium remains are the shells of two 

 turtles pertaining to the sj^ecies Stylemys nebrascensis. 



Tlie remaining fossils of the collection are mainlj' cretaceous, 

 and were obtained by Lieut. Crawford in various localities of 

 Dakota. Among them are several large specimens of Inoceramus 

 problematicus in nodules of iron stone, and fragments o{ Bacalites 

 compresHus^ together with several vertebra? of fishes, etc. 



On the Characters of Symborodon. Prof. Cope stated that the 

 fossil mammalian remains from near the Red Clond Agency, Da- 

 kota, presented this evening, probably belonged to a species of 

 Symborodon. He remarked that that genus differs from Titano- 

 therium (or Menodus) in the entire absence of inferior incisor teeth, 

 and the close approximation of tlie canines. In the last-named 

 genus the canine teet'.i of the lower jaw are widel}' separated by 

 four well-developed incisors. Dr. Leid^^ had included species of 

 Symborodon in his descriptions of Titanotherium Proutii ; thus 

 nearly or quite all of the portions of upper jaws described and 

 figured by him as belonging to the latter genus, really pertained 

 to the former, hence the erroneous assertion that Symborodon and 

 Titanotherium are identical. The u|)per jaw and superior teeth, 

 with the possible exception of one or two molars, of Titcnotlierium 

 Proutii are unknown. He added that in a few days his figures of 

 corresponding parts of tiie lower jaws of tlie two genera would 

 appear (in Hayden's Report U. S. Geological Survey Terrs. 1873, 

 Plate II.) and render tlie point clear. 



On Dr. Leidy's '^ Correction.''^ Prof. Cope stated that his record 

 of Dr. Leidy's views on the Fossil Reptilia of tlie Upper Missouri 

 Lignite, contained in Hayden's Bnlletin, IT. S. Geological Survey 

 Territories, No. 2, p. 7, whicii Dr. Leidy had deemed inaccurate,^ 

 expressed, as nearly as the case would admit of, the conclusions to 



' Proceedings of the Academy, 1874, p. 73. 



