186 BATRACHIANS. 



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

 eyelids PROTEIDA, Y. 



W. FAMILIES OF ANURA. 



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



at their tips. 



f With teeth in the jaws; 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.E, 78. 

 f f 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). PLEUIIODELID^E, 81. 

 f f Spots, if any, not as above. 

 \ Carpus and tarsus cartilaginous ; tongue much smaller and 



more extensively free than in the next, 

 a. Vertebrae concave behind only (opisthoccelian.) 



DESMOGNATHIDJS, 82. 

 aa. Vertebrae biconcave (arnphiccelian.) 



PLETHODONTIIXE, 83. 



tJ Carpus and tarsus ossified ; vertebrae amphicceli an; tongue 

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

 free margin ; salamanders usually of large size and dark 



colors AMBLYSTOMHXE, 84. 



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



size large. 



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

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



