166 THE STORY OF REPTILE LIFE. 



gation of one of the fingers, into a support for a 

 membrane or thin fold of skin, thereby converting 

 this limb into a wing, hence the name Ptero- 

 dactyle, or wing-fingered. 



In accordance with its powers of flight, we 

 iind the bones of the shoulder-girdle very strongly 

 developed, whilst the bones of the hip-girdle and 

 the hind-limbs were weak. The sternum, or 

 breast-bone, forming the base of attachment for 

 the shoulder-girdle, was well developed, and 

 furthermore bore a large keel projecting from 

 its anterior border, for the attachment of the 

 powerful muscles needed to move the wings. 

 The position of this keel, it may be noted, agrees 

 closely with that of the G-annet among birds, it 

 being placed at the extreme anterior end of the 

 .sternal plate. This resemblance is extremely 

 interesting, as it suggests that the method of 

 flight was gannet-like. And this in turn lends 

 colour to the view that these strange creatures 

 fed upon fish which they picked up from 

 amongst the shoals swimming at the surface of 

 the sea. The method of capture pursued by 

 these old Reptiles, however, probably resembled 

 that of the Terns rather than that of the Gannet, 

 which seizes its victim by plunging, like a bolt 

 from the blue, beneath the surface of the water. 



The bones of the skeleton generally, and of 

 the wings in particular, were hollow, and during 

 the life of the creature contained air, as in birds. 

 They are furthermore remarkable for their thin- 

 ness, a point of considerable importance in the 

 larger flying forms. 



The head, which was very bird-like in many 



