40 



FLYING DRAGONS. 



stituting the wings of bats. This wing was mainly supported by the great 

 elongation of the bones of the fifth digit or finger of the fore-limb, as shown in 

 the accompanying figure of the skeleton, and likewise in the restored representation 

 of one of these reptiles. The membrane thus supported seems to have extended 

 backwards along the sides of the body to include the upper portions of the legs, 

 between which it was extended to embrace the base of the tail in those forms in 



which the latter appendage was 

 fully developed. Moreover, in 

 the long -tailed species, the 

 extremity of the tail itself was 

 provided with a racket- shaped 

 expansion of membrane, which 

 may have served the purpose of 

 a rudder in flight. If it be 

 asked how the presence of such 

 membranes is known, it may be 

 answered that in many of the 

 specimens of these reptiles en- 

 tombed in the fine-grained litho- 

 graphic limestones of Bavaria 

 the actual impressions of these 

 membranes have been preserved. 

 The elongated fifth finger of 

 the wing had no claw at the 

 extremity, although the three 

 middle fingers w^ere thus pro- 

 vided. With regard to the first 

 finger, or the one corresponding 

 to the human thumb, this may 

 have been represented by the 

 small splint - like bone seen 



The creature is lying on its back, with the head bent to the left depending from the wrist in the 

 side, a indicates the left pubic bone ; the haunch-bone, or ilium, n j 1 i i. m-L i • i 



being shown on the opposite side. % Ured skeleton. The hmd- 



limbs present no special peculiar- 

 ities, but, as most of the bones of the skeleton were hollow and permeated by air, 

 like those of birds, we may infer that the lungs were probably also constructed after 

 the avian fashion. The vertebrae of the neck resembled those of living crocodiles 

 in having a ball at the hinder end of the body and a cup in front. In general 

 conformation the skull was remarkably bird-like, the snout being produced into a 

 beak, which in some cases was provided with teeth, while in others, as shown 

 in the figure on p. 5, it was toothless, and probably ensheathed during life with 

 horn. Bird-like features are likewise shown by the large size of the brain-case, 

 of which the component bones were fused together, and also by the union of the 

 extremities of the two branches of the lower jaw. 



Pterodactyles flourished during the greater part of the Secondary period, dating 

 from the epoch of the Lias, and continuing to the close of the one during which the 



SKELETON OF A ITERODACTYLE. 



