DINOSAURS. 



By S. W. WILLISTON. 



The group of Dinosaurs comprises the largest land animals 

 that have ever existed, in some cases reaching such enormous 

 proportions as to be almost incredible. In size and structure 

 they are exceedingly diverse, and of course they varied also 

 greatly in their habits. The smallest were perhaps not much 

 larger than a cat, while the largest reached a length of over 

 sixty feet and a height of fifteen or sixteen Unlike the rep- 

 tiles of the present day, none were crawling animals ; they 

 walked erect, either on two feet, after the manner of a kanga- 

 roo, which they resembled not a little in form, or upon all four 

 feet, as a quadruped. In all cases, however, the front legs were 

 smaller than the hind ones, and, in the bipedal kinds were as 

 small in proportion to the hind ones as those of a kangaroo are. 

 It is not known what kind of a skin they possessed, but in all 

 probability it was bare, without scales or bony plates, save in a 

 few forms where the body was covered in a large part, perhaps 

 wholly, by bony plates and spines. While the Dinosaurs were 

 in many respects the most specialized of the reptiles, of a higher 

 order of structure than any now living, they were, for the most 

 part, animals of a low order of intelligence. In fact, in some of 

 the very largest forms the brain was very slightly developed, an 

 animal of twenty tons weight or more having a brain no larger 

 than one's double fist. Some of the smaller species were ex- 

 ceedingly delicate in structure, having bones more hollow and 

 light than is the case with any birds known. On the other 

 hand, many of the larger forms were massive and heavy, with 

 thick, solid, heavy bones. Such may have been amphibious in 

 habit, living in marshes, lakes, and rivers, and feeding upon the 

 succulent aquatic vegetation. They were, however, in all cases 

 strictly land animals, never having the limbs in the least 



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