386 PETRIFACTIONS AND THEIR TEACHINGS. CHAP. IV. 



nature of the flora and fauna of the islands, and continents, of 

 the secondary geological epochs. 



The fossil relics of the inhabitants of the seas of the same 

 remote periods occur in such profusion, as to supply ample 

 materials for the restoration of the swarms of living things 

 that peopled the waters, through the countless centuries 

 during which the liassic, oolitic, Wealden, and cretaceous 

 formations were deposited. 



A fanciful representation of a gulf of the liassic ocean, 

 swarming with zoophytes, cephalopodous mollusca, and fishes, 

 with Ichthyosauri sporting on the billows, and devouring 

 their prey with uplifted jaws, and Plesiosauri skimming the 

 surface of the deep, and seizing pterodactyles by their 

 " leathern " l wings, is probably familiar to most of my 

 readers; for ajeu $ esprit of an eminent geologist, privately 

 circulated soon after the true characters of those marine 

 reptiles were made known, was lithographed and published 

 as a faithful delineation of the fish-like lizards, and swan- 

 necked saurians, that inhabited the seas of the liassic ages. 



The structure and economy of the Plesiosauri, as sketched 

 by the vigorous pen of their original interpreter, Mr. Cony- 

 beare, have already been fully considered; those of the 

 Ichthyosauri are portrayed by the illustrious Cuvier, in 

 characters not less graphic. 



The Ichthyosaurus was a reptile having a moderate tail, a 

 large head, with a very short neck, a long pointed muzzle, and 

 jaws armed with numerous conical teeth. Two eyes, of enor- 

 mous bulk, imparted to the head a physiognomy altogether 

 peculiar, and this great development of the organs of sight 

 jendowed the animal with nocturnal vision. It is probable 

 that it had no external ear, and that the tympanic bone was 

 covered by the skin, as in the chameleon. 



The Ichthyosaurus respired air from the atmosphere, and 

 not through a watery medium like fishes ; it must, therefore, 

 have risen frequently to the surface of the sea to breathe, like 

 the cetaceans. Its short, flat, undivided limbs, were adapted 

 only for progression through the water, and could have ad- 

 mitted but of very feeble locomotion on the land. 



1 Leathern wings of Pterodactyles, for the authority, see Prof. Owen, 

 cited ante, p. 193. 



