TADPOLES. 



55 



Fig. 13- 



from the keen eyes of other aquatic animals on the 

 look-out for food, is very interesting. If the plant be 

 present, the female smooth newt always seems to 

 prefer the leaves of the 

 Callitriche for this purpose. 

 This plant is very common, 

 and is one of the best that 

 can be selected for fresh- 

 water aquaria. The crea- 

 ture maybe seen examining 

 one leaf after another until 

 she has selected one that 

 appears to answer her pur- 

 pose better than the rest. 

 The eggs are laid at an 

 interval of three or four 

 weeks. Under the micro- 

 scope these eggs become 

 very interesting objects, in- 

 asmuch as the transparent 

 membrane allows every 

 stage of the development 

 to be plainly seen. 



The claspers are used by Callitriche, showing leaves folded 

 , , over eggs of Smooth Newt. 



the young tadpole to hold 



on to any object there is in the water, for it is only 

 after a brief experience that it is able to regulate and 

 control all its own movements. 



Water fleas (Daphnid) and the blood-worms already 



