ICHTHYOSAURS. 



59 



Arabian Chamideon calyptratus (451), of which a specimen is exhibited, 

 the body is marked by vertical bands of blue and yellow. All the 

 species are confined to the warmer parts of the Old World. 



Fio;. 41. 



The Common Chamseleou [Cliamcelcoii vultjaiis) ; § uat. size. (No. 446-1 



Order VII.— ICHTHYOPTERYGIA {Extinct). 

 (Case 17.) 



The Ichthyosaurs were Whale-like marine Reptiles which flourished 

 from the period of the Xew Red Sandstone, or Trias, to that of the 

 Chalk. The limbs are modified into paddles, in which the bones 

 of the digits exceed the normal number, and are more or less 

 shortened and broadened so as to form a pavement-like structure. 

 The teeth, which are generally fluted, are implanted in grooves in 

 the long jaws. A riug of overlapping bones is developed in the 

 white (sclerotic) of the eye. The bodies, or centra, of the vertebrae 

 are short, doubly-cupped, and separate from the nem-al arches. 



The Triassic Merrimnia and Jlixosaunis were comparatively small 

 Reptiles, iu which the ribs of the trunk are siugle-headed, the radius 



