196 THE STORY OF REPTILE LIFE. 



undergone very profound changes, indicating an 

 exclusively aquatic, probably marine, life. The 

 neck and tail have increased enormously, the 

 former containing between thirty and forty verte- 

 brae, that is to say, more than double the number 

 of the more primitive type. The tail contained 

 about the same number of vertebrae as the neck. 

 But it is in the limbs that we note the greatest 

 transformation. These have assumed the peculiar 

 paddle-shape so characteristic of the extremely 

 specialised aquatic types. The bones of the fore- 

 arm have become extremely shortened, whilst 

 the wrist and ankle bones have lost the intimate 

 relation one with another which they present in so 

 many of the terrestrial types, and have become 

 reduced to nodules imbedded in cartilage. Simi- 

 larly, the bones of the middle hand and foot 

 have become much reduced, whilst the bones of 

 the fingers have increased enormously in number, 

 to form long tapering fingers, of which the third 

 and fourth were the longest. One can picture 

 this animal, when alive, as a huge beast having 

 a swan-like neck in point of length, surmounted 

 by a relatively small head and jaws armed with 

 formidable teeth, a body like an attenuated 

 barrel, and a tail in many species rivalling the 

 neck in length, and provided with a broad fin at 

 the end. Locomotion was apparently effected 

 by the tail, whilst the paddles served as balancers. 

 Carnivorous in habit, this beast probably chased 

 and captured the curious armour-clad fishes which 

 abounded in the seas of that date, as well as the 

 smaller members of its own species. Concerning 

 the covering of the body we know nothing. 



