446 



MESOZOIC TIME. 



(4.) Pterosaurs or Flying lizards. — The flying lizards were of sev- 

 eral genera, the first known of which is Pterodactylus — so named from 

 the Greek for wing and finger, the outer finger of the hand being 

 greatly prolonged, to serve as a support for the expanded membrane 

 of the side of the body and limb, and the whole thus making a wing 

 or flying organ, analogous to that of a Bat. 



Fig. 815 represents the skeleton (reduced in size) of P. crassirostris, 



Figs. 815, 816. 



Pterosaur. — Fig. 815, Pterodactylus crassirostris (x 'i)\ 816, Coprolite. 



The species was a foot in length ; and the spread of the wings was 

 about three feet. As in Birds, the bones of Pterodactyls are hollow, 

 to fit them for flying ; but, unlike Birds, they have the skin, claws 

 and teeth of Reptiles. Their habits were those of bats rather than 

 birds. They range from the Lias into the Chalk. 



Birds. — Birds occur fossil at Solenhofen, both their bones and 

 impressions of their feathers. A specimen there found is represented 

 in Fig. 817, reduced to one fourth its natural size. The Bird, named 

 by Owen Arckasopteryx macrura (meaning long tailed ancient-bird), 

 had a tail of 20 vertebrae, 11 inches long and 3 1 inches broad, with a 

 row of feathers along either side, a pair to each caudal vertebra. The 

 wing appears to have had a two-jointed finger. 



Mammals. — The Mammals of the Jurassic have been found in 

 the Lower Oolyte at Stonesfield, and in the Middle Purbeck beds of 

 the Upper Oolyte. 



The relics from the Stonesfield slate (a bed of shelly limestone only 

 six feet thick) are referred to Marsupials, Fig. 818 represents the 

 jawbone of the Amphitherium {Thylacotherimn) Broderipii, and Fig. 



