REGENERATION IN FUNDULUS. 349 



this case, yet it is seen that the average regeneration is about the 

 same, although here again is observed the slight decrease. The 

 average regeneration of groups 2 and 3, consisting of 22 fishes 

 between 7.0 and 8.0 cm. in length, is .515 cm., while that of 

 groups 4 and 5, consisting of 21 fishes between 8.O and 9.0 cm. 

 in length, is .475 cm., showing a difference of .04 cm. between 

 the two groups. These results are shown graphically in Fig. 2, 

 in which the curve A' B' shows the relation of the specific re- 

 generation to length, while the curve C'D f shows the relation of 

 the actual amount regenerated to the length. Turning to the 

 results recorded in the former paper we find that they are less 

 satisfactory on account of the smaller numbers. But arranging 

 the results recorded there in a manner similar to that used here 

 we find that on the whole the longer fishes regenerate almost as 

 much as the shorter, although the indication of the slight diminu- 

 tion of actual regeneration with age is not so clear, which may 

 be due to the fact that there are less specimens in the various 

 groups. 



The general result seems to be then that the amount of regen- 

 eration in the period of time referred to appears to be about the 

 same in fishes of all lengths, although there is an indication of a 

 slight decrease in the case of increasing body length. 



Professor Zelenyin a paper to be published shortly (Oct., '09) 

 in the Journal of Experimental Zoology has found with respect to 

 the regeneration of the tail of the salamander, Ainblystonia jeffcr- 

 sonianum that rate of regeneration was as follows : 



In a series 22.6 mm. long there was a regeneration of .39 mm. per day. 

 " 26.5 " " .41 " 



" 26.8 " " " .39 " 



[ji 5 32 ( < 



" 54. 1 " " " .27 " 



These results agree with those described above. There is a 

 maintenance of a high degree of regenerative power in the older 

 specimens. There is also an indication of a slight decline such 

 as we found in the case of the fishes used. 



In carrying on an extensive series of observations on the age 

 of fishes Fulton ('06) estimated the age by finding the different 

 modal lengths that occurred in a large number of specimens of a 

 given species. Though the numbers used in this experiment are 



