SUPPOSED AFFINITIES OF THE FISH-LIZARDS. 125 



the swimming lizards^ would have rendered it perfectly 

 terrific ; but they were comparatively smaU animals. 

 Of two weU-ascertained species mentioned by Cuvier, 

 one seems to have been about the size of a thrush^ and 

 the other of that of a common bat. Fragments^ how- 

 ever, have been found, which are supposed to have be- 

 longed to a third and a much larger kind ; while, more 

 recently, M. Oken has made known a fourth reptile of 

 this race, which he states to have been covered, not 

 only with hair, but with feathers ! The remains of all 

 these flying-Hzards are found only in limestone slates 

 of old formation, mixed with those of numberless other 

 reptiles, gigantic tortoises and crocodiles, huge Megalo- 

 sauri, and monstrous swimming lizards of the genera 

 Ichthyosaurus and Plesiosaurus. The famous limestone 

 quarries of Germany, particularly those near Maestricht 

 and Aichstedt, are the chief deposits of these fossils ; 

 and there, no doubt, are yet buried many others of ex- 

 tinct monsters, no longer existing on the surface of the 

 earth. 



(125.) The relations of affinity between the swim- 

 ming lizards and the existing orders of reptiles, deserve 

 much consideration. When it is considered that these 

 animals possessed the exclusive power of swimming, not 

 by a slight modification in the structure of their feet, 

 but by having these members changed, as it were, into 

 absolute fins, we cannot but be struck with their total and 

 essential difference from aU other reptiles, so that we need 

 no further proof that they constitute one of the primary 

 divisions of the whole class. The question therefore is, 

 in what part of the natural series do they find a place, 

 so that all their complicated resemblances may be ex- 

 plained, either by their affinity or their analogy to other 

 reptiles. We have already intimated our belief that the 

 Enahsauri most probably occupied a station between 

 the tortoises (^Chelones) and the serpents (^Ophides'), in 

 proof of which we shaU now submit the following con- 

 siderations to the reader. 



(126.) If we admit the Enahsauri to be a group of 



