THE EMPIRE OF THE GREAT REPTILES. 



171 



Pterodactyls. These were, in short, li/aids modified for fliglit, 

 somewhat in the same manner witli the bats among the mam- 

 mals. If the bat may be likened to a flying shrew-mouse, a 

 Pterodactyl may in like manner be compared to a tlying lizard; 

 but the modification in the latter case is by much the more 

 remarkable, inasmuch as the lizard is a cold-blooded animal, 

 and far less likely to be endowed with the active circulation 

 and muscular power necessary to flight than is the mouse. In 

 point of fact, there can be no doubt that the Pterodactyls must 

 have been provided with some approach to a mammalian or 

 ornithic heart, as they certainly were with great breast-muscles 



Fig. 147. — Restoration of Rhamphorliyiicus Ihicklandi. Jurassic of England. — After 



Phillips. 



a, One of the teeth. Natural siie. 



attached to a keel in the breast-bone for working their large 

 membranous wings. These wings were also somewhat original 

 in their construction. They were not furnished with pinions, 

 like those of the bird, but with a membrane like that of the 

 bat, and this, instead of being stretched over four enormously 

 lengthened fingers, as in that quadruped, was supported on a 

 single elongated finger, corresponding, singularly enough, to 

 the little finger, which usually inconspicuous member consti- 

 tuted in some of these strange creatures a limb longer than the 

 whole body (Figs. 146, 147). The other fingers of the hand 

 were left free for walking or grasping. They are thus believed 

 to have been able to walk as well as to fly, and even in case of 



