OSTEOLOGY OF T?TE JURASSIC HEPTTLE CAMPTO- 

 SAURUS, WITH A REVISION OF THE SPECIES OF THE 

 GENUS, AND DESCRIPTIONS OF TWO NEW SPECIES. 



By Charles W. Gilmore, 



Custodian of Fo.fsil Rcptilrs, U. »Sf. National Museum. 



INTRODUCTION. 



Twenty-nine years have passed since Prof. O. C. Marsh and his 

 assistants made the first discovery of camptosaurian remains in the 

 Jurassic deposits of North America. During this period, with the 

 exception of a number of short papers prepared at various intervals 

 by Professor Marsh, little has been written concerning this inter- 

 esting group of extinct reptiles. Their apparent neglect is no doubt 

 due in large part to the dearth of material, for, despite the fact that 

 the gathering of collections has been continued with increased activity 

 during the past eleven years by representatives of the various scien- 

 tific institutions of the United States, but little new camptosaurian 

 material has been brought to light. 



The fossils upon which the present paper is largely based were 

 acquired by the U. S. National Museum through the U. S. Geological 

 Svu'vey, being contained in that part of the Marsh collection trans- 

 ferred to the Museum in 1900. The greater part of the material was 

 in the same condition as when received from the field many years 

 previous, and its preparation in so complete a condition, in view of 

 its rarity, has been most gratifying. Not only are there many indi- 

 viduals represented, but the perfection of two of the skeletons throws 

 much additional light on their structural characteristics, and it has 

 been thought advisable to give here for the first time a detailed 

 description of the osteological structure of the genus. This will be 

 followed by a discussion of the species in anticipation of defining 

 their more important characteristics. This work was made possible 

 Ijy the study of the types and other specimens contained in the col- 

 lections of the Yale University Museum, which were generously 

 placed at my disposal. 



Proceedings U.S. National Museum, Vol. XXXVI— No. 1666. 



197 



