FIG. 120. Metamorphosis of the Frog. 1, tadpole just hatched, dorsal aspect; 

 2-3, older tadpoles, side view; 4, later tadpole, dorsal view showing cutaneous 

 gills at maximum development; 5, later stage, ventral view, showing degeneration 

 of cutaneous gills and development of operculum; 6, older tadpole, left side, 

 showing single opening of operculum; 7, older stage, right side, showing hind leg 

 and anus; 8 and 10, lateral views of two later stages showing development of hind 

 legs; 9, dissection of tadpole to show internal gills, spiral intestine, and anterior 

 legs developed within operculum; 11, advanced tadpole just before metamorpho- 

 sis; 12, 13, 14, stages in metamorphosis, showing gradual resorption of tail; 15, 

 juvenile frog after metamorphosis. (From Weysse, after Leuckart-Nitsche wall 

 chart.) 



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