554 



AMPHIBIA. 



The tadpole has by this time grown large and strong while 

 feeding eagerly on water weeds. Now it seems to fast, the 

 tail shrinks, for from it wandering phagocytes carry nourish- 

 ment to other parts of the body. The habit becomes 

 less active, the structural adaptations to the aquatic life 

 disappear. "The horny jaws are thrown off; the large 

 frilled lips shrink up ; the mouth loses its rounded suctorial 

 form and becomes much wider ; the tongue, previously 

 small, increases considerably in size ; the eyes, which as yet 

 have been beneath the skin, become exposed ; the fore- 

 limbs appear ; the left one being pushed through the spout- 



FlG. l88. — Life history of a Frog. (After Brehm.) 



1-3. Developing ova ; 4. newly hatched forms hanging to water 

 weeds ; 5-6. stages with e.vternal gills ; 7-10. tadpoles during emer- 

 gence of limbs ; II. tadpoles with both pairs of limbs app.-irent ; 12. 

 metamorphosis to frog. 



like opening of the branchial chamber, and the right one 

 forcing its way through the opercular fold, in which it leaves 

 a ragged hole." (Marshall.) 



While these changes are in progress, and as the supply of 

 food afforded by the tail begins to be exhausted, the tadpole 

 recovers its appetite, but is now carnivorous, feeding on any 

 available animal matter, or even on its fellows. The change 



