512 COLLEGE ZOOLOGY 



Eustachian tubes open by single aperture; no distinct 



tympanic membrane; vertebrae opisthoccelous. 

 Family AGLOSSID^E. With the characters of the sub- 

 order. Examples: Pipa (Fig. 434), Xenopus. 

 Suborder 2. LINGUATA (PHANEROGLOSSA). FROGS and 



TOADS. SALIENTIA with a tongue; Eustachian tubes 



open by two apertures. 

 Family i. PELOBATID^E. Spade-foot toads. Examples: 



Pelobates, Scaphiopus. 

 Family 2.. BUFONID.E. TOADS. Examples: Bufo, Rhi- 



nophrynus. 

 Family 3. HYLID.E. TREE-FROGS. Examples: A cris, 



Chorophilus, Hyla, Nototrema (Fig. 435). 

 Family 4. CYSTIGNATHID^E. Examples: Hemiphractus, 



Hylodes, Paludicola. 

 Family 5. ENGYSTOMATID^E. Examples: Engystoma, 



Phryniscus, Hypopachus. 

 Family 6. RANID^E. TRUE FROGS. Examples: Rana, 



Phyllobates, Oxyglossus. 

 Suborder 3. COSTATA (DISCOGLOSSID^E). SALIENTIA with 



a tongue; Eustachian tubes open by two apertures; 



with short ribs. 

 Family DISCOGLOSSID.E. With the characters of the 



suborder. Examples: Discoglossus, Alytes, Bom- 



binator. 



3. REVIEW OF THE ORDERS AND FAMILIES OF LIVING 

 AMPHIBIA 



Order i. Apoda. The single family, CcECiLinLE, of this 

 order includes about forty species of worm-like or snake-like leg- 

 less AMPHIBIA. They inhabit the tropical regions of America, 

 Africa, India, Burma, and northern Australasia, but none occurs 

 in the United States. They burrow in moist ground with their 

 strong heads, and, as a result of living in darkness, their eyes are 



