EXTINCT REPTILES. 339 



The vertebrae differ mucli in this group in size and number. As a rule the bodies were slightly 

 concave before and behind, or nearly flat ; but in some instances the cervical vertebrse were hollow 

 behind only, the dorsal were flat, and those of the tail amphiccelous. Chevron bones were attached 

 between the tail vertebrse; and the sacrum appears not to have been formed by less than four 

 vertebrse. These reptiles had long narrow scapulae, no clavicles, and the coracoid was rounded. The 

 femur is bird-like at its farther end, and the inner and outer digits are either shorter than the rest or 

 quite rudimentary ; and the third digit is the longest, as in the birds in general (Huxley). The bones 

 of the pelvis were much like those of birds. 



THE OENITHOSAUEIA. 



Flying reptiles, but not fashioned on the principle of the modern little Dragon, existed in the 

 Secondary age of the world, and must have been common in Europe and America. The largest had 

 a spread of wing of from ten to twenty-five feet, and were found fossil in the remains of the inland 

 Cretaceous sea of North America. Smaller than these, but furnished with teeth (which the others 

 had not), were those of Europe, some of which were as large as the Albatross, and others no larger 

 than a Blackbird. The American kinds are called Pteranodontia, and the European Pterodactyles. 

 In some of the European kinds there were no teeth in the front of the jaw, and the others were implanted 

 in sockets, but there was a beak (Ramphorhynchus). This kind had a very long tail. In others 

 (Dimorphodon), the front teeth were large and pointed, and the others small. The true Pterodactyles 

 had short tails, teeth throughout the jaws, and the little finger with four long joints. A membrane 

 was attached to them, to the fore arm, to the flanks of the body down to the tail, and it stretched 

 thence to the ankle, and passed over to the end of the little finger. No other fingers were inchided 

 in the great skin wing. No feathers existed, but the limb-bones were hollow and light. The 

 breast-bone had a keel like the flying birds, and there was a scapula, and also a coracoid very bird- 

 like. The head had great orbits, and was long and light, and a ring of sclerotic plates was on the 

 eye. The brain-case was like that of the bird. They lived in the age of the Lias to that of the 

 Cretaceous inclusive. 



THE ICHTHYOPTEEYGIA. 



An order of extinct reptiles, the Ichthyopterygia,* contains gigantic massive forms which 

 combined a fish and lizard-like construction, and were highly predaceous. They had a long head, a 

 veiy indistinct neck or fish-like body, and a long tail. The body was covered with skin, and not with 

 scales or plates, and there was probably an upright fin oil the tail, which added to the compressed look 

 of the body. Huge eyes, whose sclerotic had many bony plates, were placed at the side of the head ; 

 and the gape was wide, the teeth long and stout, and not planted in sockets, but in a common groove. 

 They breathed by means of lungs, and the ribs were numerous, false ones being developed, on the under 

 part of the abdomen. The vertebra were very numerous, and the bodies biconcave, and the neural 

 arch was united to them by a distinct suture. There were neither sternum nor sternal ribs, and the 

 sacrum consisted of two vertebrse ; but scapulae, coracoids, clavicles, and interclavicles existed. The 

 fore and hind limbs were in the form of paddles, the digits consisting of numerous groiips of five, 

 with extra or marginal bones. The similarity of these in plan to those of the Cetacea or Whales is 

 very remarkable. These reptiles attained a vast size, and flourished especially in the Lias of 

 Europe, and lived to the close of the Secondary age. They could swim by the side lash of the 

 tail and the propelling action of the paddles ; and doubtless, from the size of the orbit, the large 



* Fish-fin. 



SKELETON OF ICHTHYOSAURI, S, 



