10 



8 



FlG. 30. Metamorphosis of Rana temporaria. i, tadpole just hatched ; 2, 3, successively 

 older tadpoles seen from one side; 4, a slightly older tadpole seen from the ooisal side ; 5, 

 a still older specimen from below; 6, taduolr with the gills covered, leaving only a small 

 opening on the left side; 7, first indication of hind legs; 8 and 10, successively older stages; 

 9, specimen with the ventral bod\ wall removed, showing the coiled intestine and gills; n, 

 both pairs of legs free ; 12, 13, 14, successive stages in the resorption ot the tail; 15, adult 

 frog. A, anus; HE, hind leg; A' gills; AX, gill opening; .!/, mouth; A', nasal opening; 

 O. eye; SN, ventral sucker. (From Weysse's "Synoptic Text Book of Zoology," after 

 Leuckart and Nitsche.) 



117 



