412 THE AMERICAN NATURALIST. 
t.e. it may be that the fry reared at Woods Holl would attain 
‘to a larger number of dorsal fin-rays than the same fry reared 
at Waquoit. 
_ While certain experiments that the writer has made induce 
him to believe that these variations in the number of dorsal 
fin-rays may be deep-seated blastogenic characters, the influ- 
ence of the environment, even if it should affect the onto- 
genic process, cannot vitiate the method, for if it is insisted that 
certain external influences may affect the fry after liberation 
from the hatchery, and the results of these influences are 
expressed by a change in the fin-ray formula, it must also be 
equally true that the more extreme and unusual environmental 
conditions imposed upon the still younger organism while wethin 
_ the hatchery, will leave their stamp also, and the artificially 
hatched fish will thus present some peculiarity, acquired though 
it may be, which will be brought out by the plotting of “curves 
of distribution.” 
