REGENERATION IN FUNDULUS AND ITS RELATION 

 TO THE SIZE OF THE EISH. 



G. G. SCOTT. 



Przibram ('09) in his treatise on regeneration has reviewed the 

 work bearing on the relation between the age of the animal and 

 the ability to regenerate. The general conclusion is in the form 

 of a law " Die Regenerationsfahigkeit nimmt mit zunehmenden 

 Alter eines Tierexemplares ab ." In the BIOLOGICAL BULLKTIN 

 ('07) the author came to the conclusion that the regeneration of 

 the caudal fin of Fitnduhis heteroclitus was greater in the shorter 

 than in the fishes of medium length and greater in these than in 

 the longest fishes. 



That conclusion was reached by comparing the average specific 

 regeneration of the various groups. The specific regeneration is 

 obtained by dividing the actual amount regenerated by the length 

 of the animal, giving as a result the percentage amount regener- 

 ated by that specimen. This term was introduced by Zeleny. 

 Now if we take any number and divide it successively by a series 

 of numbers each greater than the preceding we will obtain a series 

 of quotients each successively smaller and smaller. On referring 

 to the experiments in his former paper the author found that the 

 actual amounts of regeneration differed but little in the various 

 specimens used, while the length of the animals increased, so that 

 the case is as stated above--/, c., that the greater specific regen- 

 eration in the shorter fishes is due largely to the fact that the 

 divisor in case of short body length is smaller than the divisor in 

 case of long body length, while the dividend (the actual amount 

 regenerated) is about the same, so that naturally we should get 

 smaller and smaller quotients, which in this case would be specific 

 regeneration. This is seen when we refer to the former paper. 



To test the matter further the writer repeated the experiment 

 during the summer of 1908 using a larger number of fishes. 

 The caudal fin of each specimen was removed at the same rela- 

 tive level on August 4 and the fish were placed in running sea- 



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