 By the end of the larval stage , the tadpoles already have limbs and metamorphosis takes place normally . In salamanders , this occurs over a short period of time and involves the closing of the gill slits and the loss of structures such as gills and tail fins that are not required as adults . At the same time , eyelids develop , the mouth becomes wider , a tongue appears , and teeth are formed . The aqueous larva emerges onto land as a terrestrial adult . 
