PERENNIBRANCHIATE BATRACHIA. 



99 



less complete than in the Frog, being checked at a less 

 advanced stage. Thus in the common Water-Newt, the tail 

 is retained during the whole of life, and the animal continues 

 to be an inhabitant of the water, though breathing air alone. 

 There are some very curious animals, however, in which the 

 change is stopped, as it were, at a much earlier period, so that 

 the gills also are retained ; and in these, the lungs are suffi- 

 ciently developed to enable the animals to breathe air, so that 

 they can live either on land or in water. Such Batrachia are 

 scientifically known as perennibranchiate, this term express- 

 ing the persistency of their gills. In fig. 40 is represented 



Fig. 40. AXOLOTL. 



an animal of this kind, the Axolotl, which inhabits some of the 

 lakes of Mexico. And in fig. 41 is shown the form of a still 

 more remarkable animal, the Lepidosiren, or mud-fish, recently 





Fig. 41. LEPIDOSIREN. 



brought from th.3 rivers of Africa, the metamorphosis of 

 which appears to be checked at a still earlier period, so that 

 it is very difficult to decide whether it should be regarded as 



H 2 



