22 



ILLINOIS BIOLOGICAL MONOGRAPHS 



[22 



TABLE 17 

 Series 3676-3765 Less than 4 millimeters removed Summary Tables 10 to 16 



Note 1. Because of the great variability in the data of the average for the 

 four-day period is not of much value and is therefore not included in the grand 

 average. 



Note 2. The absorption of the regenerated portion of the tail was pro- 

 ceeding so rapidly by the fifty-fifth day of regeneration that this average 

 should not be included in the grand average. 



Experiment III Series 3557-3624 



This experiment was planned for a study of the effect of repeated 

 removal and regeneration upon the rate of metamorphosis but it yields 

 data of value for the present problem. Tadpoles of Rana clamitans 

 with an average length of about 40 mm. were used. In some cases 

 the cuts were made inside of the first level and therefore in old 

 tissue and in other cases outside of the first level and therefore in new 

 tissue. 



The data include third, fourth and fifth successive regenerations. 

 The time of regeneration is 37 days for the third and 36 days for the 

 fourth and for the fifth regenerations. The length of time is more than 

 sufficient for the completion of the process of regeneration in so far as 

 it is completed. The data therefore do not serve for the rate but for 

 the completeness of regeneration from old as compared with new levels. 

 Approximately one-half of the original tail length was removed but 

 measurements were not made of individual removed lengths, so that 



