STUDIES IX THE EXPERIMENTAL ANALYSIS OE SEX. 277 
tlie presence of a large amount of lutein in tlie blood, or that 
it only occurs after a period of active lutein formation, tlie 
difficulty would be cleared up, and we could confidently say 
that the condition in Sacculinised Inaclius was the same as 
the condition of normal maturing females, where tetron- 
erythrin does appear in the blood towards the end of the 
maturing process. 
Unfortunately, we have at present no facts to support this 
view, andvthe collection of sufficient quantity of blood from 
Inachus may prove a severe, though perhaps not insuperable, 
difficulty in testing the point. 
We will leave the question of pigmentation for the present 
and turn to the question of moulting and the storage of 
glycogen associated with it. 
The deposition of large quantities of glycogen under the 
skin of crabs as a preparation for the moult has been long 
known in the case of Decapods, but it can also be shown to 
occur in Entomostraca, such as Daphnidae. The late Mr. 
'G. H. Grosvenor put some notes at my disposal on the intra- 
vitam staining of various Daphuids with neutral red. He 
found that by keeping Moina for twenty hours iii water to 
which a little neutral red had been added, certain cells in the 
epidermis became brightly coloured owing to the avidity with 
which certain refringent bodies contained in their cells took 
up the stain. On starving a Moina for twenty-four hours and 
then making it take up neutral red, it Avas found that these 
cell-inclusions were greatly reduced in size. From the simi- 
larity in appearance, situation and staining reaction Avhich 
these bodies bear to the glycogen deposits in Carcinus, there 
can be no doubt that they are also composed of glycogen, and 
represent the material from which the new integument is 
formed. 
The reduction o,f» these reserve deposits during starva- 
tion is significant, as there is no doubt that in Carcinus also, 
during starvation, glycogen is removed from the skin and 
used in the general metabolism, probably after being con- 
veyed to the liver, since, as will be shown, starvation for a 
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