§ 26. ENALIO-SAURIANS, OR MARINE LIZARDS. 573 



ble from the skeleton : but, from the peculiarity of the 

 terminal vertebras of the tail, Prof. Owen concludes that 

 the original had a strong vertical caudal fin.* There are 

 many species, some of which are of a magnitude equal to 

 that of young whales. The teeth are conical, sharp, and 

 striated, resembling those of crocodiles in the power of 

 reproduction, but differing in the number, situation, and 



Lign\ 127. — Restored figure of the Ichthyosaurus. 

 (From Mr. Hawkins.) 



mode of regeneration ; one species has 110 in the upper, 

 and 100 in the lower jaw; they are arranged in a deep 

 furrow or groove, not in sockets, and were retained only by 

 the integuments. The orbit is very large, and the sclerotic, 

 or outer coat of the eye, is made up of thin bony plates, 

 arranged round the central opening or pupil, as in the owl 

 and other birds ; a mechanism by which the power of the 

 eye is materially increased, and vision adapted to near or 

 remote objects at will. The bones forming the sternum, 

 or chest, which protect the organs of respiration, are strong 

 and largely developed, and the sternal arch offers a remark- 

 able correspondence with that of the Ornithorhyncus, 

 of Australia. 



Like turtles, the Ichthyosaurus had four paddles, composed 

 of numerous bones enveloped in one fold of integument, so 

 as to form an entire fin, as in the cetacea ;f the fore-paddles 



* Medals, p. 712. 



f The soft integuments of the paddle are occasionally preserved : 

 See the figure of a beautiful example from Barrow-on-Loar, " Medals of 

 Creation," p. 713. 



