AMPHIBIANS 137 



Key to the Suborders of the Caudata 



ai Two pairs of legs present i. Mutabilia (p. 137). 



a2 But one pair of legs present 2. Meanies (p. 155). 



Suborder i. Mutabilia. — Both pairs of limbs present; both 

 jaws with teeth; a single ossification in the shoulder girdle: 7 families, 

 grouped in 2 superfamilies. 



Key to the Superfamilies and Families of Mutabilia 



ai Prearticular and angular bones in lower jaw separate; adult 

 with second epibranchial; female without spermatheca; 



fertilization external Supcrfamily A. Cryptobyauchidea. 



bi Large flattened, river dwelling forms; teeth on prevomer 



close to and parallel to those on maxilla i. Cryptobranchidce. 



32 Prearticular and angular bones fused; adult without second 

 epibranchial; female with spermatheca; fertilization 



internal Superfamily B. Salamandroidea. 



hi Smaller in size; more or less cylindrical forms; larvae, 

 if small, with 5 toes. 

 Ci Ypsiloid cartilage and lungs present; no naso-labial 

 groove; no parasphenoid teeth, 

 di Vomerine teeth in 2 longitudinal rows, diverging 



posteriorly; costal grooves not marked 2. Pleurodelidce. 



d2 Vomerine teeth in transverse series; costal grooves 



marked 3. AmbystornidcE. 



C2 Ypsiloid cartilage and lungs absent; naso-labial 

 groove present in adults; parasphenoid teeth pres- 

 ent in adults 4. PlethodontidcB. 



bs Eel-like in form, and of larger size; larvae, if large, with 

 4 toes. 



Ci Legs minute, w'ith 2 to 3 toes 5. Amphiumidce. 



Co Toes 4 on all feet 6. Proteidce. 



Family i. Cryptobranchidae. — Giant salamanders. Body stout 

 and of large size; a pair of small gill-slits usually persistent; vertebrae 

 amphicoelous; carpus and tarsus cartilaginous; no eyelids; vomerine 

 teeth form an arched series parallel with the jaws: 2 genera, one of 

 which, Megalobactrachus, is found in China and Japan and contains 

 but one species, M. japonicus (Hoeven), which grows to a length of 

 6 feet and is the largest salamander. 



Cryptobranchus F. S. Leuckart. Fore legs with 4 and hind legs 

 with 5 toes each; gill slits always persistent: i species. 



C. alleganiensis (Daudin). Hellbender. Body dark brown in 

 color; head and trunk depressed, tail compressed; prominent lateral 

 fold present; length 480 mm.; tail 160 mm.: western New York and 

 central Pennsylvania to Georgia and Louisiana; westward to Iowa; 

 Mississippi drainage; Susquehanna; aquatic; often common. 



