Haicher: Gknera anh Si-kciks oi Tkachodontid-k. ^81 



founded on fragmentary lumbar and caudal vertebrae, the last two on 

 poorly preserved caudal vertebrae. 



In 1S70 Cope proposed the genus and s[)ecies Hypsihcina crassicaiida 

 for the reception of some caudal vertebr;^ and fragmentary limb- and 

 foot-bones belonging to one of these dinosaurs which he described in 

 the Transactions of the American Philosophical Society for 1870, and 

 in the Proceedings of the same Society for 187 1. 



The next genus and species proposed for these dinosaurs was Ciono- 

 don cvcfafus''^ Cope, first described in 1S74, and founded on a portion 

 of a right maxillary with several teeth in position found in Colorado, 

 no more definite locality being given. In the succeeding year ( 1 875)'" 

 Professor Cope gave a further description of this genus, adding a new 

 species C. Steiicypsis, founded on material collected by the late Dr. 

 G. M. Dawson said to be from the Ft. Union beds of the Milk River 

 region, Canada. At that time, as now, the Ft. Union and Laramie 

 deposits were not easily distinguishable, and it is quite probable that 

 this material was from a horizon approximately the same as that of the 

 other material from the West upon which the foregoing genera and 

 species have been proposed. 



In the same year Professor Cope proposed still another new genus, /•(;/)'- 

 gonax, for these dinosaurs. He described the species as P. mortnariiis, 

 founded on three dorsal vertebrre and some fragments of limb bones 

 found in Colorado" in association with the remains referred to Ciono- 

 don arctatus. 



In 1876 '• the genus Dicloniiis was proposed by Cope for the reception 

 of certain remains of these predentate dinosaurs and three new species, 

 D. pentagomis, D. perangulatis, and D . calainariiis, were introduced, 

 based on shed teeth found associated according to that author with 

 those of TracJiodon iiiirabilis in the Laramie (Ft. L^nion) deposits. 



On page 99 of the Proc. of the Phil. Acad, of Sci. for 1S83, in 

 his " Characters of the Skull in the Hadrosauridne " Cope, says, " The 

 species on which these observations are based is the Dicloniiis inira- 

 bilis of Leidy," and in a footnote he adds, "This species is part of 

 one called by Leidy Trachodon mirabilis, who included in it a species 



9 Hull. U. S. G. S. of the Terrs., No. i, 1875, p. 2. 



'oVert. of Cre. form, of the West, Rep. U. S.G. S. of the Terrs., Vol. IL, 1875, 



PP- 57-63. 



"See Rep. on the Vert. Pal. of Col., -Vn. Rep. U. S. G. S. Terrs, for 1873, pub. 



1875. PP- 451-452. 



'-See Proc. Phil. Acad. Sci., 1S76, pp. 253-255. 



