448 The Flying Lizards of the Secondary BocJcs. 



case "with analogous modifications in the form and strength of 

 the beaks of birds, and in the jaws and teeth of animals. 



Professor Owen* suggests that P. brevirostris and another 

 species (P. Meyeri) were probably immature Pterodactyles, as 

 they show the large cranium, short jaws, and unossified ster- 

 num, characteristic of the early period of life in crocodiles of 

 the present day.f 



But we find in this order such singular modifications, both 

 in the dentition and the form and length of the jaws, as to lead 

 to the supposition that it might include (like the Bats) genera 

 with insectivorous, carnivorous, and possibly even frugivorous 

 habits. The head, however, has always a more or less elon- 

 gated form, and is lightened by large vacuities interposed 

 between the nostril and the orbit. The vertebras of the neck 

 are about seven in number, and united by ball and socket joints, 

 the hollow being in front. In almost all known specimens the 

 neck vertebrae are the largest, and the entire series gradually 

 diminishes to the sacrum, and terminates with a more or less 

 long and slender tail. 



The fore-arm consists of a short humerus, a radius and 

 ulna of nearly equal size, and placed closely together ; carpal 

 and metacarpal bones, supporting four fingers, armed with 

 claws, and a fifth or outermost digit (consisting of four joints), 

 which is elongated like the four digits in the bat, and serves, 

 to sustain the membranous wing upon which the animal was 

 upborne in flight. 



The head of the humerus was supported by the union of the 

 coracoid and scapula ; and although the furculum, or " merry- 

 thought" (so characteristic a bone in birds), is absent, we often 

 find the sternum more or less perfectly preserved, and furnished 

 with a very deep keel for the attachment of strong pectoral 

 muscles by which the expansive wings of the Pterodactyle 

 were moved. 



" It is almost superfluous to remark that the evidence of the 

 fore limbs had shown the Pterodactyle to have been a flying 

 animal long before anything was precisely known as to its 

 sternum. The development of the keel of the sternum in the 

 Pterodactyle exceeds that of any of the bat tribe ; and it may be 

 confidently concluded that the flight of the winged reptile 

 might have been at least as swift and of as long continuance as 

 in the Pteropi. But, viewing the lightness of the bones of the 

 Pterodactyle, and the relatively greater development of the in- 

 terpcctoral crest of the sternum, Professor Owen J believes it to 

 have been a creature of more extensive, continuous, and power- 



* I'alceonMoqy, second edition, 18G1, p. 274. 



+ Gray, On Skulls of Young Garldal and Crocodile. British Association, 1862. 



X Palscontl. Society, Suppt. No. iii., Fossil Rcptilia Cretaceous Formation, p. 11. 



