120 CLASSIFICATION OF AMPHIBIANS. 



Anahgies of the cheloxian reptiles to the 



VEBTEBRATED CLASSES. 



Families of *„„7„„,-^. Classes of the 



Tortoises. Analogies. Vertebrata. 



TestuOiniO.. ["^^^ ^L^^!''^'}^^^^. 



Emydce. Sub-typical; move quickly. Birds. 



^, ,„ ., ("Tail excessively long, covered7T> ^-i 



Ckehdnd<s. I ^vith scales. j Reptiles. 



TrionkidiB.', Covered ivith a naked skin. Amphibians. 



Chelonidce. Feet transformed into fins. Fish. 



On sho-wing this and the preceding table to an intelli- 

 gent friend, but who was no naturalist, he observed that 

 such expositions would carry conviction of their truth 

 to every mind, because they exhibited a degree of unity 

 in all branches of the creation hitherto unimagined, 

 and yet on principles so simple, that they could be 

 comprehended by any one, whether naturalist or not, 

 who merely knew the leading points of our theory. 

 To naturalists, indeed, who are unprejudiced, nothing, 

 as we conceive, can be more definite than the circular 

 succession of the tortoises, and the representation they 

 thus give of the primary types of all other animals. 

 Having now taken a rapid view of two out of the three 

 aberrant groups of the class, we shall treat of the third 

 in more detail, on account of its important relation to 

 reptiles, to fishes, and to birds. 



(121.) The Enalosaures, or fish-lizards, form the 

 third and last aberrant division of the reptiles. Of these 

 wonderful animals, whose fossil remains distinguish the 

 older strata of our globe, no living example has been 

 discovered : they all belonged, apparently, to a former 

 state of the world ; yet their determination is of very 

 recent date. Before we investigate the relations which 

 these monsters seem to bear to existing reptiles, we 

 shall notice two of the most striking, which will give 

 the reader a tolerably good idea of the typical characters 

 of the whole ; these are the Ichthyosaurus and the P/e- 

 siosaurus^ 



