188 PETRIFACTIONS AND THEIR TEACHINGS. CHAP. III. 



expanse, have a remarkably small skull, with beaks furnished' 

 in some species, with upwards of sixty sharp-pointed teeth? 

 and generally very long. The teeth are simple, of a conical 

 form, recurved, and implanted in distinct sockets, with con- 

 siderable intervals between them. The orbits are very large, 

 and the neck elongated. The sternum and pectoral arch are 



LIGN. 42. PTERODACTYLE, FROM SOLENHOFEN. ($ nat. size.) 

 (PTERODACTYLUS CRASSIROSTRIS.) 



constructed as in reptiles. The peculiar organization of the 

 fore-foot, and which entirely differs from that of any other 

 reptile, whether recent or fossil, consists in the great extension 

 of the fore-finger, which is composed of five bones, and exceeds 

 in length the entire spinal column ; the other digits are Of 

 the ordinary relative proportions, and armed with claws, i 

 Impressions of the delicate membranous expansion, or wing, 

 which this finger was designed to support, are occasionally 



1 There are excellent figures of Pterodactyles in Dr. Buckland's 

 " Bridgewater Essay," PI. XXI. and PI. XXII. 



