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PALEONTOLOGICAL BULLETIN, No. 23. 



[Extracted from the Proceedings of the Academy of Natural Sciences of Philadelphia, 



December, 1876.] 



ON SOME EXTINCT REPTILES AND BATRACHIA FROM THE JUDITH 

 RIVER AND FOX HILLS BEDS OF MONTANA. 



BY E. D. COPE. 



LiELAPS, Cope. 

 Proceed. Acad., Phila., 1866, p. 275. Extinct Batr. Rept. N. Amer., 1869, p. 100. 



Two species of this genus were described in the latter memoir 

 above cited, the L. aquilunguis, Cope, and L. macropus, Cope, both 

 from the greensand or Fox Hills group of the cretaceous of New 

 Jersey. A considerable portion of the skeleton of the former 

 was described, including the peculiarities of the ankle-joint, which 

 led me to the conclusion, previously unsuspected by naturalists, 

 that the Dinosauria present affinities to the cursorial birds. The 

 teeth of this species were described and figured, but in the L. ma- 

 cropus they were, and still remain, unknown. 



In a preliminary report on the extinct vertebrata obtained b}^ 

 the writer on the Upper Missouri the present year, three addi- 

 tional species were referred to this genus, viz. : the Lselaps 

 incrassatus ; L. explanatus, and L. falculus. Their characters 

 were ascertained from teeth alone, so that their pertinence to the 

 genus Lselaps is not fully assured. A fourth species of carniv- 

 orous dinosaurian was described under the name of Aublysodon 

 lateralis. 



One of the most valuable specimens obtained by my expedition 

 of 18*76, is the nearly entire left dentary bone of the Lselaps incras- 

 satus, which exhibits the teeth of its two extremities. The different 

 forms of the teeth of the carnivorous Dinosauria graduate into each 

 other by such easy stages, as to have given rise to question in ref- 

 erence to their proper interpretation ; whether they indicate differ- 

 ent species or only different positions in the dental series. In de- 

 scribing the Aublysodon horridus, the first known of the species of 

 the Judith River beds, Dr. Leidy expressed the suspicion that a cer- 

 tain form characterized the teeth in the position of incisors, another 

 those in the position of canines, and another form the remainder 

 of the series. The teeth of the last kind have the form of those 

 of Lselaps; in others the posterior serrulate cutting edge is 

 1 



