Fig. 13-24. A tree toad (Hy/a versicolor) croaking. Note the greatly extended vocal sacs which aid in producing 



its shrill sound. 



Fig. 13-25. The great bullfrog (Rana cafesbiana), which 

 may reach a length of a foot over-all. The large ear- 

 drum identifies this as a male. 



Fig. 13-26. A pair of toads in amplexus. 



