0. 0. Marsh — Restoration of Brontosaurus. 341 



The main characters which separate the group from all other 

 known families of the Dinosauria are as follows : 



(1) A rostral bone, forming a sharp, cutting beak. 



(2) The skull surmounted by massive horn-cores. 



(3) The expanded parietal crest, with its marginal armature. 



(4) A pineal foramen. 



(5) The teeth- with two distinct roots. 



(6) The anterior cervical vertebrae coossitied with each other. 



(7) The dorsal vertebrae supporting, on the diapophysis, both 

 the head and tubercle of the rib. 



(8) The lumbar vertebrse wanting. 



The animals of this group were all herbivorous, and their 

 food was probably the soft succulent vegetation that nourished 

 during the Cretaceous period. The remains here "figured are 

 from the Ceratops beds of the Laramie, and were found by 

 Mr. J. B. Hatcher, in Wyoming, on the eastern slope of the 

 Rocky Mountains. 



Restoration of Brontosaurus. 



On Plate XVI is a restoration, one-ninetieth natural size, of 

 another large Dinosaur, the gigantic Brontosaiirus of the 

 Jurassic. This differs so widely from Triceratops of the 

 Cretaceous that a comparison of the two is most instructive. 

 Each represents the dominant reptilian type of the period in 

 which it lived, and each belongs to a distinct order of the 

 Dinosauria. The older form, Brontosaurus, was more than 

 double the size of the later Triceratops. The former 

 represents a more primitive type, and the latter, one highly 

 specialized. Both show the early character of locomotion on 

 all four feet, which many allied forms of each appear to have 

 nearly or quite lost before their extinction. 



In the restoration of Brontosaurus, the diminutive head 

 will first attract attention, as it is smaller in proportion to the 

 body than in any reptile hitherto known. The neck was very 

 long and flexible. The body was rather short. The legs and 

 feet were massive, and the bones all solid. The tail was very 

 long and powerful. The animal during life must have been 

 nearly sixty feet in length, and about fifteen feet in height. 

 Its probable weight was more than twenty tons. 



Brontosaurus was herbivorous in habit, and its food was 

 probably aquatic plants or other succulent vegetation. The 

 skeleton here represented was found in the Atlantosaurus 

 beds of the upper Jurassic, in Wyoming, west of the Rocky 

 Mountain range. 



