268 PROCEEnlNG^ OF THE NATIONAL MUSEUM. vol. xxxvi. 



genera Camptosaurus Laosaurus, and Dryosaurus, N a7iosaurus be- 

 ing retained under the family Nanosaiiridse as originally proposed 

 by Marsh. 



In the same year, Zittel'^ defines the genus Camptosaurus thus: 



Attaining a total length of at)out 10 m. Cervical ribs short ; dorsal vertebne 

 amphiplatan ; sacrals not anchylosed. Pubis robust, postpubis of equal length 

 with the long and slender ischium. Pendant inner fourth trochanter of femur 

 marked. Pi-oximal tarsals separated. 



As shown by a recent study of the tyj^ical specimens in conjunc- 

 tion with all other available material, it is found that the earlier 

 definitions of the genus, as briefly reviewed above, are in some re- 

 spects in error. Such inaccuracies as have been detected caii, in most 

 instances, be attributed to the incompleteness of the material at the 

 command of the earlier authors. 



The characters displayed by the discovery of new material, com- 

 bined with a restudy of the typical specimens, show that the genus 

 Camptosaurus may now be characterized as follows : 



Generic characters. — Premaxillaries edentulous., with horny heak. 

 Teeth large., irregular and comparatively few in number. A supra- 

 orbital fossa. Cervical vertebrae posterior to the third opisthocoelous 

 manus with five digits., metacarpal of first digit ankylosed with 

 radiale. Ilium with long preacetabular process. Pubis well devel- 

 oped., with broad anterior blade., postpubis elongated reaching end of 

 ischium. Ischium toith long shaft terminated by an expanded ham- 

 'mer-like end. Femur curved., longer than tibia., xoith pendant inner 

 trochanter extending on to the distal half of the shaft. Astragulus 

 and calcaneu7)i free., former without ascending process. Pes robust 

 with four digits., first being rudimentary. 



C amptosaurus dispar is the tj^DC-species of the genus, and, as will 

 be discussed later, was founded on the remains of at least two and 

 maybe three individuals, all from the Jurassic, Quarry No. 18, near 

 Como, Albany County, Wyoming. Eight species have been described 

 .as pertaining to this genus, of which four are American and four 

 European. An alphabetical list of the species assigned to the genus 

 is given below. 



ALPHABETICAL LIST OF SPECIES." 



Camptosaurus ampins Marsh. (No. 1879, Yale University 

 Museum.) 



Camptosaurus browni, new species. (Cat. No. 4282, U.S.N.M.) 



« Text-book of Paleontology, English Tianslation, II, 1002, p. 23S. 



" lu P^oldtaui Kozlouy, Budapest, XXXI, 1901, p. 210, Nopcsa inadverently 

 includes Dryosaurus alius (Marsh) in a list of the described species of 

 Camptosaurus. Marsh first described this form as Laosaunis alt us and later 

 referred it to Dryosaurus. While it represents a closely related genus, it is 

 quite distinct from Camptosaurus. 



