192 BULLETIN OF THE 
to faint nuclei, with their delicate radiating spokes indicating faintly 
the former extension of the dark chromatophores (Figs, 11-15). The 
colored pigment cells seem to be far less influenced by the color of the 
bottom upon which the young fishes are placed; they contract some- 
what, but are never reduced in size as much, or in the same proportion, 
as are the black cells. (Compare Figures 9 and 16.) The question 
of heredity involved in the changes due to the growth of flounders 
from a symmetrical embryo to an unsymmetrical adult, are naturally 
suggested by the development of the flounder. They have an important 
bearing on the transmission of acquired character, and seem to have 
escaped the notice of most writers on the subject. 
In the case of young Lobsters, while still pelagic, the changes in col- 
oring were quite marked; they pass, during the first month of their 
growth, from green to brown, but thus far my attempts to change or 
modify their coloring by the action of differently colored bottoms have 
not been successful. Nor have I succeeded any better with the young 
embryonic stages of Crangon and Palsemon, in which the tail and thorax 
are marked by few large and prominent pigment cells. The Crusta- 
ceans were kept, during parts of several seasons, subject to very differ- 
ent influences of light and surroundings, but without producing any 
perceptible change in coloration. 
December, 1892. 
