246 HISTORICAL PALAZONTOLOGY. 
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 1s 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 vertebree 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 
vertebre ; whereas in all existing Birds the tail is abbreviated, 
and the terminal vertebree 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 Prerosaurs 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 
