334 



HISTORICAL GEOLOGY. 



FIG. 280. Jurassic in- 

 sects : Blattina for- 

 mosa. (After Heer.) 



Reptiles. These are the rulers of the age, and cul- 

 minate in this period. We shall therefore dwell a little 

 more fully on them. During the Jurassic there was a truly 

 extraordinary development of this class, in number, size, 

 variety, and degree of organization. They were rulers in 

 every department of Nature : rulers in 

 the sea, in place of whales and sharks of 

 to-day; rulers on the land, in place of 

 beasts ; and rulers in the air, in place 

 of birds. We shall take them up under 

 the three heads indicated, viz.: 1. Ma- 

 rine Saurians (Enaliosaurs). 2. Land 

 Saurians (Dinosaurs). 3. Winged Sau- 

 rians (Pterosaurs). The first were swim- 

 ming, the second walking, the third fly- 

 ing, animals. 



1. Marine Saurians. Among these 

 we shall mention only the two most noted, 

 viz., Ichthyosaurus and Plesiosaurus. 

 The Ichthyosaurus (fish-reptile) (Fig. 

 282) was a huge monster, thirty to forty 

 feet long, with thick body, short neck, 

 enormous head, eyes twelve to fifteen 

 inches in diameter, and jaws set with 

 hundreds of conical teeth. The limbs 

 were paddles, suitable for swimming, not for walking. 

 The powerful tail was expanded vertically into a fin at its 

 extremity, and the bodies of the vertebrae were biconcave 

 like those of a fish. Perfect skeletons of this animal 

 have been found ; and even the impressions of its intes- 

 tines, and the contents of its stomach, revealing the 

 nature of its last meal, have been preserved. 



The Plesiosaurus (lizardlike) (Fig. 283) was a slenderer 

 animal, with a very long neck, small head, short tail, long 

 and powerful paddles, and fishlike vertebrae. 



2. Dinosaurs, or Laud Saurians. The hugest of 



FIG. 281 Glaphyrop- 

 tera gracilis. (After 

 Heer.) 



