204 • PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxvi. 



OSTEOLOGY OP' CAMPTOSAURUS. 



In the following pages an attempt is made to give a detailed de- 

 scription of the complete osteology of Camptosaurus, which, to a 

 great extent, is based upon material preserved in the paleontological 

 collections of the U. S. National Museum. This is supplemented, 

 however, in many instances, and corroborated in others, by a study 

 of the types and other specimens in the Yale University Museum, the 

 collections of these two institutions containing the greater portion of 

 the known Camptosavi^vs material from the Jurassic of this country. 



Primarily the detailed description of the skeleton is based on Cat. 

 No. 4282, U.S.N.M,, holotype" of the new species, C. hrowni. I 

 have selected this specimen on account of its representing a consid- 

 erable portion of one individual, concerning the association of whose 

 parts there can be but little question raised. Reference will occasion- 

 ally be made to other individuals, where important structural dift'er- 

 ences are displayed, and bones not represented in this skeleton will 

 be described from other specimens. 



THE SKULL. 



A complete articulated skull of Camptosaurvs is unknown, al- 

 though nearly all of its comiDonent parts have been recognized from 

 the several disarticulated and fragmentary crania now preserved in 

 the collections of the National and Yale museums. 



Marsh was the first to attempt a restoration of the skull, wliich was 

 based primarily upon the disarticulated elements of No. 1880 (holo- 

 type of C. fnedius), and the well-preserved anterior and posterior 

 portions of No. 1887, Yale Museum, shown in Plates 7, 8, and 9 of the 

 present paper. The latter specimen represents a very much larger 

 individual, and, as suggested elsewhere, probably pertains to a dis- 

 tinct species. Thus the skull as figured could hardly be distinctive 

 of C. medius, as formerly considered. 



The restoration presented here (see figs. 2 and 3) is based upon the 

 one given by Marsh, with such corrections and emendations as better 

 preserved and more abundant material renders possible, and while 

 it is anticipated that future discoveries will undoubtedly show the 

 present restoration to be in error in some particulars, still it is be- 

 lieved that a clearer and more correct conception of the skull of 

 Camptosaurus is given than could be obtained from the earlier repre- 

 sentations. 



«This is a term defined by Schucliert (Bull. U. S. Nat. Mus., No. 53, Pt. 1, 1905, 

 p. 10) : "A liolotyi^e in natural history is a particular individual deliberately 

 selected by the author of a species, or it may be the only example of a species 

 known at the time of original publication. A holotype, therefore, is always a 

 single individual, but may embrace one or more parts, as the skin, skeleton, or 

 other portions, such as the obverse and reverse of a natural mould." 



