2 5 ANIMAL LIFE PAST AND PRESENT. 



capable of active flight, are described at length in a 

 later chapter, our allusion to them will here be brief. 

 These extraordinary creatures/as shown in Fig. 11, were 

 furnished with thin membranous wings, supported in 

 front by the arm and fore-arm near the body, and at 

 their extremities by the greatly extended joints of a 

 finger corresponding either to the ring or little finger 

 of the human hand. This membranous expansion was 

 continued down the sides of the body to embrace the 



Fir,. 11. Restoration of a Long-tailed Pterodactyle. One-seventh natural size. 

 (After Marsh.) 



legs and the upper part of the tail ; while in at least 

 some of those species in which the tail was long, its 

 extremity was furnished with a racket-shaped expan- 

 sion of membrane (as in Fig. 11), probably used as a 

 kind of rudder during flight. Some of these creatures 

 were of enormous dimensions, having an expanse of 

 wing estimated at upwards of 25 feet. That they 

 were endowed with the power of true flight is perfectly 

 evident from their general structure; as is especially 

 shown by the strong ridge developed on the breast- bone 



