244 



ANOURA. RANAD^. 



sooner in warmer climates, the little Tadpoles 

 are hatched. They appear to consist of an enor- 

 mous head and a long, thin, vertically flattened 

 tail ; from the hinder part of the head, on each 

 side, are seen to project two minute tufts, divided 

 into branched leaflets. These are the hranchice 

 or gills, by means of which oxygen is separated 

 from the water for the renewal of the vital power 

 of the blood. These tufts rapidly enlarge, and 

 soon attain their greatest development, in which 

 state they form, as Mr. Bell assures us, one of 

 the most charming objects for microscopic ob- 

 servation which can be conceived, and to view 

 which a very high power is not necessary nor 

 even desirable. The current of the blood poured 

 in regular pulsations at each contraction of the 

 heart, passes up each stem or main branch of 

 the branchiag, and a distinct stream is given off" 

 to each leaf ; it is propelled to the extremity, and 



&^. 



TADPOLES. 



then returns down the opposite sides in the most 

 regular manner, and the parts are so transparent 



