186 BATRACHIANS. 



ft External branchiae and gill clefts persistent through life ; no 

 eyelids PKOTEIDA, Y. 



W. FAMILIES OF ANURA. 



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



at their tips. 



f Upper jaw with teeth; toes completely webbed. 

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



RANID^E, 77. 



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

 spur ; fingers scarcely webbed ; chiefly terrestrial. 



SCAPHIOPID^, 78. 

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



restrial BUFONID/E, 80. 



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

 arboreal HYLID.E, 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 very rarely obsolete) ; 

 belly dotted with black ; tarsus and carpus ossified ; verte- 

 brae opisthoccelian (not biconcave). PLEURODELDXE, 81. 

 ft Spots, if any, not as above. 

 \ Carpus and tarsus cartilaginous ; tongue much smaller and 



more extensi\ 7 ely free than in the next. 

 a. Vertebrae concave behind only (opisthocceliau.) 



DESMOGNATHID^E, 82. 

 aa. Vertebras biconcave (ainphiccelian.) 



PLETHODONTID^E, 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^E, 84. 



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



size large. 



6. Limbs well developed ; toes 4-5. . . MENOPOMID^E, 85. 

 bb. Limbs rudimentary ; toes 2-2 or 3-3. . AMPHIUMID^E, 86. 



