THE GREAT FISH-LIZARDS. 45 



is known that many attained much greater dimensions. Judging 

 from detached heads and parts of skeletons, it is probable that 

 some of them were between thirty and forty feet long. A 

 specimen of Ichthyosaurus platyodon in the collection of the 

 late Mr. Johnson, of Bristol, has an eye-cavity with a diameter 

 of fourteen inches. This collection is now dispersed. 



With regard to their habits, Sir Richard Owen concludes that 

 they occasionally sought the shores, crawled on the strand, and 

 basked in the sunshine. His reason for this conjecture (which, 

 however, is not confirmed by Dr. Fraas's recent discoveries) is to 

 be found in the bony structure connected with the fore-paddles, 

 which is not to be found in any porpoise, dolphin, grampus, or 

 whale, and for want of which these creatures are so helpless when 

 left high and dry on the shore." The structure in question is a 

 strong bony arch, inverted and spanning across beneath the chest 

 from one shoulder to the other. A fish-lizard, when so visiting 

 the shore for sleep, or in the breeding season, would lie or crawl, 

 prostrate, with its under side resting or dragging on the ground — 

 somewhat after the manner of a turtle. 



It is a curious fact that this bony arch resembles the same part 

 in those singular and problematical mammals, the Echidna and 

 the Platypus, or duck-mole. 



The enormous magnitude and peculiar construction of the eye 

 are highly interesting features. The expanded pupil must have 

 allowed of the admittance of a large quantity of light, so that the 

 creature possessed great powers of vision. 



The organic remains associated with fish-lizards tell us that 

 they inhabited waters of moderate depth, such as prevails near a 

 coast-line or among coral islands. Moreover, an air-breathing 

 creature would obviously be unable to live in " the depths of the 



' It is, perhaps, hardly necessary to remark that whales are not fishes, but 

 mammals which have undergone great change in order to adapt themselves 

 to a marine life. Their hind limbs have practically vanished, only a rudiment 

 of them being left. 



