2398 CROCODILES, DINOSAURS, AND FLYING DRAGONS 



America; some of these toothless members of the order far exceeded auy flying oird 

 in point of size; the estimated span of wing in the largest species being upward of 

 five-and-twenty feet. This group may be distinguished not only by the total 

 absence of teeth, but likewise by the great backward extension of the hinder 

 extremity of the skull. 



In the typical pterodactyles (Pterodactylus, etc. ) the jaws were provided with 

 teeth, which may, however, have been very small in size and few in number, 

 while the skull, as shown in the figure of the skeleton on p. 2397, was not pro- 

 duced backwardly, and the tail was reduced to a rudiment. The members of this 



RESTORATION OF A LONG-TAILED PTERODACTYLS- 



(One-seventh natural size.) 



(After Marsh.) 



group, which are common in the Oolitic rocks of the Continent, vary in size from 

 the dimensions of a sparrow to those of an eagle. Lastly, we have the long-tailed 

 pterodactyles (Rhamphorhynchus, etc.), which are likewise of Oolitic and Liassic 

 age, and are at once distinguished, as shown in the restoration, from the members 

 of the preceding group by the fully-developed tail. These long-tailed species are 

 evidently the most generalized members of the order; and in the retention of the 

 tail in the generalized group, and its loss in the more specialized one, the reader 

 will not fail to notice an exact parallelism between ordinary bats and the more 

 highly-developed fruit bats. 



