THE EXTINCT DINOSAURS 



2391 



in the circumstance that the vertebrae of the neck and back, as shown in the accom- 

 panying figure, had large cavities in their sides, which in the living state may have 

 been filled either with cartilage or with air. These vertebrae resembled those of 

 existing crocodiles, as described on p. 2361 in having a ball at one end and a cup at 

 the other; but whereas in crocodiles the ball is at the hinder end of the body and 

 the cup in front, in these dinosaurs precisely the reverse of this arrangement ob- 

 tained. As regards their dentition, these reptiles had their teeth implanted in dis- 

 tinct sockets, like crocodiles; but the teeth themselves, as shown in the accompany- 

 ing figure, were of a peculiar spatulate shape, with the outer side convex and the 

 inner concave. Agreeing in the general structure of their pelvis with crocodiles, these 



LEFT SIDE VIEW OF AN IMPERFECT VERTEBRA 

 OF A LIZARD-FOOTED DINOSAUR. 

 (From the Quart. Journ. Geol. Soc., 1893.) 



INNER AND LATERAL VIEWS OF A TOOTH 

 OF A HOPLOSAUR. 



dinosaurs were distinguished therefrom by the circumstance that the bone known 

 as the pubis (p in the figure on p. 2359) enters into the composition of the cavity 

 for the reception of the head of the thigh bone. The limb bones are solid 

 throughout. From the nature of their teeth, which are often much worn by use, 

 it may be inferred that these reptiles were vegetable feeders; and it is not improb- 

 able that they frequented the margins of lakes and rivers, where their inordinately 

 long necks would enable them to browse with ease on the various aquatic plants. 

 That they must have been very sluggish in their movements and stupid in their 

 ideas is indicated by the wonderfully small proportionate size of their brains. These 

 dinosaurs were common both in Europe and the United States, the larger forms 



