AMPHIBIA. 



28 7 



opus includes the burrowing spade-foot toad which is rarely 

 seen except at the breeding-season. Allied European genera 

 are Alytes and Bombinator. The 

 HYLID.E have teeth, while the 

 tips of the toes are expanded into 

 sucking-disks. Our tree-toads be- 

 long to Hyla, Acris, and Choro- 

 philus ; Notodelphys and Nototrema, 

 tropital America. The extinct 

 PAL^OBATRACHID^: (oligocene) 

 are noticeable for two sacral ver- 

 tebrae. 



ORDER III. FIRMISTERNIA. 



FIG. 285. Shoulder girdle of 

 Bombinator igneus, showing the ar- 

 ciferous type, after Wiedersheim. 

 f, clavicle ; c0, coracoid ; ec, epi- 

 coracoid ; g, glenoid fossa ; /<:, pro- 



Tongue well developed; epi- corac< ? id; '' scapula; JJ ' supra - 



scapula ; sf, sternum. 



coracoids firmly united in the 



median line. The ENGYSTOMID.E, or toothless frogs, occur in 



our southern states. Engy- 

 stoma. The RANID.E, or 

 true frogs, have smooth 

 skin, and teeth in the up- 

 per jaw. Rana contains 



our species including the; 

 bullfrog (A*, catesbianay 

 the largest known frog. 

 Sternum and R ana fi rs t appears in the 



the Boulder 



j Numerous other 



after Wieders- 



the firmister- families in the tropics, in- 



FIG. 286. 

 ventral portion of 

 girdle of Rana, 

 heim, illustrating 



nous type of sternum, cl, clavicle ; co, cora- eluding the DENDROBA- 

 coid; ec; epicoracoid ; g, glenoid fossa ; as, TIDJE w hich have tOCS like 

 omosternum; s, ventral part of scapula; st, 

 sternum; x, xiphisternum. tne tree-toads, Hylldae. 



SUB-CLASS IV. GYMNOPHIONA (CffiCILLffi). 



Limbless amphibia of worm-like shape ; tail lacking; vertebrae 

 amphicoelous ; skull well ossified, with well-developed ethmoid ;. 

 body externally ringed, and bearing semi-circular dermal scales. 

 Frequently a protrusible tentacle in a tentacular sheath between 



