ON THE IDENTIFICATION OF FISH ARTI- 
FICIALLY HATCHED. 
HERMON C. BUMPUS. 
ALTHOUGH the United States Fish Commission has annually 
hatched and planted many millions of young fish, and although 
the planting has often resulted in the apparent increase in the 
number of adults where the plantings have been made, there 
is nothing but circumstantial evidence to show that the fish 
appearing in increased numbers are really the adults of the 
young artificially produced. The recent excessive abundance 
of cod along the shores of New England is probably the result 
of extensive operations at the Woods Holl hatchery. The 
facts that these fish were small when they first appeared, that 
they have since increased in size, that they have occurred in 
localities where cod had never before been caught, and that 
they are reported to be of a different color from the native 
variety are interesting, although to the sceptical they are not 
absolutely convincing. There is need of some scheme whereby 
the adults of fish hatched artificially may be distinguished from 
those native to the locality. 
To mark the fry is, of course, out of the question, but is it 
not possible that the fry mark themselves, z.e., is there not 
a slight difference between the fish of the same species but of 
different localities, and if there is this slight difference, does 
it not present itself in a measurable manner ? 
The careful examination of a large number of periwinkle 
shells! (Littorina littorea) has shown that localities even near 
together are characterized by shells of different proportions. 
This fact has warranted the examination of a number of fish 
for the purpose of seeing if they too are not subject to similar 
varietal changes. 
During the latter part of March of the present year, while 
1 Zoölogical Bulletin, vol. i, No. 5, February, 1898, p. 247. 
