246 HISTORICAL PALEONTOLOGY. 



been found fossilised ; but we could determine that the " Ptero- 

 dactyles ".possessed the power of flight, quite apart from the ex- 



Fig. 178. Pterodactylus crassirostris. From the Lithographic Slates of Solenhofen 

 (Middle Oolite). The figure is " restored," and it seems certain that the restoration is 

 incorrect in the comparatively unimportant particular, that the hand should consist of no 

 more than four fingers, three short and one long, instead of five, as represented. 



traordinary conformation of the hand. The proofs of this are to 

 be found partly in the fact that the breast-bone was furnished 

 with an elevated ridge or keel, serving for the attachment of 

 the great muscles of flight, and still more in the fact that the' 

 bones were hollow and were filled with air a peculiarity 

 wholly confined amongst living animals to Birds only. The 

 skull of the Pterosaurs is long, light, and singularly bird-like in 

 appearance a resemblance which is further increased by the 

 comparative length of the neck and the size of the vertebrae of 

 this region (fig. 178). The jaws, however, unlike those of any 

 existing Bird, were, with one exception to be noticed hereafter, 

 furnished with conical teeth sunk in distinct sockets ; and 

 there was always a longer or shorter tail composed of distinct 

 vertebras ; whereas in all existing Birds the tail is abbreviated, 

 and the terminal vertebrae are amalgamated to form a single 

 bone, which generally supports the great feathers of the tail. 



Modern naturalists have been pretty generally agreed that 

 the Pterosaurs should be regarded as a peculiar group of the 

 Reptiles ; though they have been and are still regarded by 

 high authorities, like Professor Seeley, as being really referable 



