CLASS AMPHIBIA 



473 



Size. — While most modem Amphibia are small creatures, paleon- 

 tological species reached large proportions, as, for example, the 

 Mastodonsaurus, which had a skull 4 feet long and a total length 

 of probably 15 or 20 feet. Among living amphibians, the giant 

 salamander of Japan and China, Megalobatrachus japonicus, grows 

 to a length of 5 feet. In the Southwest, the largest salamanders 

 are Siren lacertina, which attains a length of about 30 inches, and 

 the "hellbender," Cryptobranclnis, which commonly grows to be 



Fig. 259. — The caecilian, Ichthyophis glutinosus, adult female, guarding her 

 eggs on the left, and a larva showing external gills on the right. Partly after 

 Sarasins. (From Atwood : Introduction to Vertebrate Zoology, published by The 

 C. V. Mosby Company.) 



about 18 inches long and AmpMuma, the Congo eel. The goliath frog 

 of Africa reaches a body length of nearly a foot, while southern bull- 

 frogs, larger than their northern relatives, may grow to be over 7i/2 

 inches in body length, with a total length of 16 to 18 inches when the 

 legs are extended. The giant toad or marine toad, Bufo marinus, is 

 the largest of the true toads, and attains a body length of 8% inches. 

 The smallest frog in the United States is the swamp tree frog, Pseu- 

 dacris ocularis, which ranges from North Carolina to southern 

 Florida. Adults measure only % to % of an inch in body length. 



