CARNIVOROUS GROUP. 



35 



INNER AND OUTER VIEWS OF A TOOTH OF A PELOROSAUR. 



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



dinosaurs were distinguished therefrom by the circumstance that the bone known 

 as the pubis (p in the figure on p. 3) 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 improbable 

 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 propor- 

 tionate size of their brains. These 

 dinosaurs were common both in 



Europe and the United States, the larger forms having been described under the 

 names of pelorosaurs (Pelorosaurus), atlantosaurs (Atlantosaurus), brontosaurs 

 (Brontosaurus), and hoplosaurs (Hoplosaurus) ; among which the atlantosaurs 

 appear to have been the most gigantic. They also occur in India, Argentina, 

 and Madagascar. 



o 



Carnivorous The carnivorous dinosaurs, of which the 

 Group. megalosaur (Megalosaurus) is the best known 

 example, differed from the preceding group in the form of 

 their teeth, which were compressed and sickle-shaped, with 

 sharp cutting, and frequently serrated edges. Their limb- 

 bones also were hollow ; while their vertebrae were likewise 

 hollow internally, but had no lateral cavities ; and the 

 pelvis (figured on p. 3), although of the same general 

 type as in the lizard-footed group, presented important 

 points of distinction. In place of the short feet of the 

 last-named group, the carnivorous dinosaurs had elongated 

 foot -bones, terminating in sharp claws; the number of 

 functional toes in the hind-foot varying from four to three. 

 That they habitually walked on the toes of their hind- 

 limbs, and not (as was the case with the lizard-footed 

 group) on the whole foot, is evident from the structure of 

 this part of the skeleton, and from the circumstance that 

 the fore-limbs were considerably smaller than the hinder 

 pair, it may be inferred that progression was at least 

 frequently accomplished by the aid of the latter alone. 



JBONES OF THE RIGHT HIND- m -, . . . . , , , , , P , , 1 1 i. 



FOOT OF A CARNIVOROUS n6 c l se approximation of the huckle-bone or the ankle to 

 DINOSAUR. the lower end of the tibia foreshadows the complete 



