186 BATRACHIANS. 



f f External branchiae and gill clefts persistent through life ; no 

 eyelids. Psotbida, Y. 



W. FAMILIES OF ANURA. 



* Fingers and toes tapering or cylindrical, not dilated into a disk 



at their tips, 

 t Upper jaw with teeth ; toes completely webbed. 

 a. No spur at the heel ; fingers often webbed ; chiefly aquatic. 



Ranid^, 77. 

 aa. One of the bones of the heel forming a sharp, flat-edged 

 spur; fingers scarcely webbed ; chiefly terrestrial. 



SCAPHIOPrDiE, 78. 



•ft Jaws toothless ; toes webbed; skin more or less warty; ter- 

 restrial BUFONID^, 80. 



** Fingers and toes dilated at their tips, forming a viscous disk; 

 arboreal 'B.ylidx, 79. 



X. FAMILIES OF URODELA. 



* No spiracles or openings in the sides of the neck in the adult. 



■•• Sides (in our species) with a row of round red or yellowish spots 

 which are bordered with black (these veiy rarely obsolete) ; 

 belly dotted with black ; tarsus and cai-pus ossified ; verte- 

 brse opisthocoelian (not biconcave). Pleurodelid^, 81. 

 f f Spots, if any, not as above. 

 J Carpus and tarsus cartilaginous ; tongue much smaller and 

 more extensively free than in the next. 

 a. Vertebrse concave behind only (opisthocoelian.) 



DBSMOQNATHID.a!, 83. 



aa. Vertebrse biconcave (amphicoelian.) 



PLBTHODONTIDiB, 83. 



}::|: Carpus and tarsus ossified ; vertebrae amphicoelian; tongue 

 large, thick, papillose, attached by its base, with a narrow 

 free margin; salamanders usually of large size and dark 



colors Amblystomid^, 84. 



** With a spiracle or rounded opening in each side of the neck : 

 size large. 

 b. Limbs well developed ; toes 4r-5. . . Menopomidm, 85. 

 66. Limbs rudimentary ; toes 3-3 or 3-3. . AMPHrnMiDiB, 86. 



