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LILLIE AND KNOWLTON. 



[VOL. I 



TABLE VIII. Growth in length of toad tadpoles at different temperatures. 13.5 units equal 

 i mm. The last three readings are from one lot of tadpoles, and their difference from the 

 others represents individual variation. They are not included in the curve. 



FIG. 4. Curve of growth of the tail of toad tadpoles constructed from the above table. The 

 ordinates represent units (13.5 =1. i mm.) of growth and the abscissae degrees Centigrade. 



the toad tadpole and that the latter continues to grow at a 

 higher temperature (see table, not shown in curve) than the 

 former. This is correlated with the fact that the eggs of the 

 toad are laid later than those of the frog and generally in smaller, 

 shallower pools, the temperature of which is relatively high ; 

 this has caused acclimatization to a higher range. 



