APPEN DTX. 



Akt. XXIII. — Restoration of Camptosaurus ; bv 

 O. C. Marsh. (With Plate VI.) 



The Jurassic deposits of western North America contain 

 the remains of many gigantic Dinosaurs, and various skeletons 

 of these have been obtained by the writer, who has described 

 the more important forms. Restorations of the skeletons of 

 three of the most interesting genera, Brontosaurus, Stego- 

 saurus, and Ceratosaurus, have already been given in this 

 Journal, and another of these huge reptiles is thus represented 

 on Plate YI accompanying the present article. Each of the 

 three forms previously restored was a typical member of a 

 distinct group of the Dinosauria, and this is true, although in 

 a less degree, of the present genus, Camptosaurus. Restora- 

 tions of Anchisaurus from the Triassic, and Olaosaurus and 

 Triceratops from the Cretaceous, all Dinosaurs of much 

 interest, have likewise been published by the writer in the 

 present Journal.* 



The restoration here given is based upon the type specimen 

 of Camptosaurus dispar, one of the most characteristic forms 

 of the great group Ornithopoda, or bird-footed Dinosaurs. 

 The reptile is represented on Plate VI, one-thirtieth natural 

 size. The position chosen was determined after a careful 

 study not only of the type specimen, but of several others, in 

 excellent preservation, belonging to the same species or to 

 others nearly allied. It is therefore believed to be a position 

 frequently assumed by the animal during life, and thus, in 

 some measure, characteristic of the genus Camptosaurus. 

 The present species, when alive, was about twenty feet in 

 length, and ten feet high in the position here represented. 



The genus Camptosaurus is a near ally of Iguanodon of 

 Europe, and may be considered its American representative. 

 Camptosaurus, however, is a more generalized type, as might 

 be expected from its lower geological horizon. It resembles 

 more nearly some of the Jurassic forms in England gene- 

 rally referred to Iguanodon, but, as these are known only 

 from fragmentary specimens their generic relations with 

 Camptosaurus cannot now be determined with certainty. 



In comparing Camptosaurus, as here restored, with a very 

 perfect skeleton of Iguanodon from Belgium, as described 

 and figured, various points of difference as well as of resem- 

 blance may be noticed. The skull of Camptosaurus had a 

 sharp, pointed beak, evidently encased during life in a horny 

 sheath. This was met below by a similar covering, which 

 enclosed the predentary bone. The entire front of the upper 

 and lower jaws were thus edentulous, as in Iguanodon, but of 

 different shape. The teeth of the two genera are of similar 



*This Journal, vol. xli, p. 339, April, 1891; vol. xlii, p. 179, August, 1891; 

 vol. xliv, p. 343, October, 1892; and vol. xlv, p 169, February, 1893. 



