272 BIOLOGY FOR BEGINNERS 



Book, Dickerson, pp. 53-239; Elementary Zoology, Davenport, pp. 325- 

 348; Practical Zoology, Davison, pp. 199-211; Elementary Zoology, Gallo- 

 way, pp. 296-305; Pet Book, Comstock, pp. 246-259; Handbook of Nature 

 Study, Comstock, pp. 181-199; Nature Study Leaflets (bound), pp. 185- 

 206. 



SUMMARY 

 Metamorphoses of Frog. 



Meaning of term, other examples, tadpole is "frog larva." 

 Egg, laid in water, surer fertilization, in spring. 

 Gelatinous protection, parts show in 10 days. 

 Tadpole (attached stage). Discs, three external gills. 



Lives on yolk. Two weeks. 

 Tadpole (free swimmer), mouth develops. 



Long intestine because vegetable feeder (explain). 

 Lateral line, caudal fin, operculum with left opening. 

 Two-celled heart, fish-like. Two months. 

 Tadpole, frog. 



Mouth widens, intestine shortens, teeth develop. 

 Heart three celled, arteries change from gill to lung. 

 Lungs develop, air used, skin breathing. 

 Tail absorbed, legs develop. One month. 

 Adult frog. 



Total time about three months, depends on food, temperature, etc. 

 Representatives. 

 Frog. 



Toad, false ideas, real value. 

 Adaptations for food-getting. 

 . Tongue as in frog, no teeth. 



Color, skill. 

 Distinctions from frog. 



Toad Frog 



Eggs in strands Eggs in masses 



Nocturnal feeding Daytime feeding 



Tadpoles small, black Tadpoles larger, lighter 



No teeth at all No teeth on lower jaw 



Rough skin Smooth skin 



Tree toad (Hyla). 

 Adaptations, color protection, color change. 



Discs for climbing, vocal sacs. 

 Tadpoles reddish, early develop lungs, eat insects. 

 Salamanders. 



Distinctions from lizards. 



Salamander Lizard 



Common Not common 



Smooth skin like frog Scaled skin like snake 



No claws on feet Claws on feet 



Metamorphosis like frog No metamorphosis 



Harmless, useful and interesting. 



