FURTHER NOTES ON THE REGENERATION OF 

 THE FINS OF FUNDULUS HETEROCLITUS. 



G. G. SCOTT. 



During the last summer the writer while engaged as assistant 

 at the biological laboratory of the U. S. Bureau of Fisheries at 

 Woods Hole, Mass., conducted various experiments on Fundnlus 

 iicteroclitns. Since a number of these can be conveniently 

 grouped under the heading regeneration they are collected and 

 presented in the present paper. Various factors determining 

 regeneration have been under discussion and it was thought that 

 these should be tested using Fundnlus h. as a type since it is a 

 representative teleost and that therefore results might differ from 

 those obtained in crustaceans, for example, and that certain princi- 

 ples deduced from crustacean work might possibly have to be 

 modified. Thanks are due to Dr. F. B. Sumner as director of 

 the laboratory of the Bureau of Fisheries for assistance in provid- 

 ing the necessary apparatus and other facilities. 



The following experiments were designed to show : (<?) the 

 relation of temperature to regeneration, ($) the relation of degree 

 of injury to regeneration, (<r) the relation of length and weight 

 (/. e., age) of specimen to regeneration, (W) the relation of amount 

 of food to regeneration, (V) adaptation in regeneration. 



(A) RELATION OF TEMPERATURE TO REGENERATION. 



With a view of testing this the caudal fin of ten Fundithts Ji. 

 were cut in a line as near as possible to the origin of the caudal 

 fin rays. The same procedure was followed in all the later cases 

 to be described. These fish were placed in a chest or jar with 

 three liters of sea water and the jar placed in an, ice chest where 

 the temperature averaged I4C. The water was changed every 

 day or so. On August 24 five fish had survived. The fish had 

 not been fed. The survivors had been under observations for 41 

 days or almost six weeks. But in those survivors there was no 

 sign of regeneration. With fishes in normal conditions regenera- 



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