REPORT ON THE OCCUPATION OF A TABLE 
AT THE 
CULLERCOATS MARINE LABORATORY. 
By F. W. FEEBLE, M.A.. and F. W. GAMBLE. D.S< . 
Wo have been engaged during the greater part of this year 
(1000) in a research on the colour-physiology of Macromysis inrnnis. 
This research is a continuation of our former work ( / 'roceedinys of 
the Royal Society, 1900. 1000) on the development and 
significance of colour in Crustacea. 
Our subject, Mysis, occurred in great abundance off Cullcrcoats 
during the late spring and summer, and proved of the utmost value 
in enabling us to understand the reactions of the so-called chromato- 
phores to light, and other stimuli. Its excellence for this purpose 
is due to the high transparency of the body, as well as to the limited 
distribution and orderly arrangement of the chromatophores. 
We have succeeded in showing that both quality (colour) of light 
and light- intensity may act as stimuli to colour change ; but that in 
all probability the former is a factor which does not make itself felt 
under natural conditions. 
Further, the contraction and expansion of the chromatophores, 
and consequently the colour of the animal are independent — within 
wide limits — of the intensity and nature of the incident light, but are 
sharply determined by the quantity of light reflected from the sub- 
stratum. The creatures offer a most extraordinary instance of 
sensitiveness, interpreted in colour-change, to minute changes in the 
quantity of reflected light. Thus, for example, light admitted into 
a dark chamber through two or three pin holes is sufficient to bring 
about a redistribution of pigment if the background be changed 
from black to white during the experiment. 
Beyond these brief indications of the results to which our experi- 
ments lead we do not now propose to go, since we wish to extend 
our observations to other members of the Crustacea, and also to other 
groups of animals. 
