HEPTILES. 303 



" We consider that the porteus is not an amphibious ani- 

 mal, having a double circulation, as some have maintained, 

 but a perfect reptile, different entirely from all others. It 

 is a reptile, in respect to its having a single circulation, and 

 a fish, in regard to its mode of respiration, in other 

 words, it is a reptile which respires air mixed with water, 

 while others respire atmospheric air : so that, were it allow- 

 able to revive the old idea of a chain of beings, the proteus 

 might be regarded as the link which would connect reptiles 

 with fishes. 1 " 



Gills permanent. 



There are no lungs, but in the situation which they oc- 

 cupy in the preceding group, there are two bags with sim- 

 ple membranaceous walls. 



67. APNEUMONA. Feet four, with three toes before 

 and two behind. 



The only well characterised species, is the A. anguina y 

 which inhabits the waters of subterranean caverns in Car- 

 niola in Germany, where it lives excluded from the light. 

 The genus to which it belongs, has been usually denomi- 

 nated Proteus, which we have ventured to change for ano* 

 ther title expressive of the want of lungs. The term Pro- 

 teus had been long preoccupied, as the name of a genus of 

 infusory animals, remarkable for the mutability of their 

 forms ; two species of which are delineated by MULLER, in 

 his Animalcula Infusoria, Tab. II. Fig. 1.-12. and 13.-18. 

 Besides, the reptile under consideration is nowise remark- 

 able for mutability of form. 



b. Destitute of a tail. 



This section includes the different kinds of frogs and 

 toads. The eggs are fecundated as they are deposited. 

 They are surrounded by a glaire, which has properties in- 

 termediate between gelatine and albumen, and which in- 



