So ANIMAL LIFE PAST AND PRESENT. 



are all deposits formed by the sea, so that we are led 

 to conclude that these saurians were of marine habits. 

 Again, it may be observed that whereas in the Lias the 

 remains of the Fish-Lizards are usually found in the 

 condition of more or less nearly complete skeletons, with 

 every bone but little shifted from its natural position ; 

 in the overlying rocks the skeletons are dislocated and 

 often imperfect. Although the latter condition renders 

 us sometimes unable to restore the complete skeleton 

 of these later forms, yet it has the compensating 

 advantage that we are able to handle and examine the 

 individual bones in a manner which is generally quite 

 impossible with the skeletons from the Lias, where the 

 bones are often distorted and flattened by pressure. 



We are now in a position to consider a few of the 

 more prominent features in the structure of these 

 primeval saurians, of which the whole organisation is 

 better known than that of most of the other reptiles of 

 the same epochs. In the woodcut (Fig. 17, p. 54) we give 

 a copy of Sir Kichard Owen's restoration of the entire 

 skeleton, together with a conjectural outline of the 

 contour of the body when clothed with flesh and skin. 

 It will be seen from this that the contour of the entire 

 animal was of a whale-like type; there being no 

 distinct neck, the body gradually passing into the tail, 

 and the two pairs of limbs forming paddles, or flippers, 

 adapted, like those of a turtle, for propelling the body 

 through the water, and perhaps also permitting their 

 owner to crawl awkwardly on the sea-shore in the 

 same manner as the turtle does. From the circum- 



