272 
GKOFFKKY SMITH. 
I'm tty material from the blood similar to that which the ova 
absorb in a normal female is shown to be accurate. 
It is not known in what form the fat is present in the blood 
of crabs. Although analysis shows fat to be there it is impos- 
sible to detect the presence of neutral fat in the undecomposed 
blood, so that we must presume that it is combined with some 
other substance in the blood, and is split off by the ova or by 
the Sacculina roots and deposited as neutral fat within these 
tissues. 
2. On Moulting anl> the Fokmviton of Pigment. 
We have now to examine the effect exerted by Sacculina on 
pigmentation, moulting, and the glycogen-metabolism con- 
nected with moulting. 
In previous work (2 and 3) Robson and I have shown that 
the blood of male crabs, especially in the periods leading- 
up to a moult, becomes charged with a pink lipochrome, the 
destination of which is the skin. It was shown that this pink 
lipochrome was accompanied with a very small quantity of 
fat as compared with the yellow lipochrome present in the 
blood of females with ripening ovaries. Nevertheless, I 
hazarded the opinion that this pink lipochrome with its 
accompanying fat was used in the skin as reserve material 
from which the new skin might in part be formed. If, how- 
ever, frozen sections of the skin underlying the hard shell of 
a crab be treated with fat staining reagents, it is found that 
practically no fat can be detected. Although no fat is present 
there are large masses of reserve material in the dermis in the 
foini of irregularly shaped refringent clumps which stain 
intensely with neutral red. These deposits, as is well known, 
consist of glycogen — a fact which can be most easily demon- 
strated by extracting with boiling water and adding iodine 
solution, when the reddish-broAvn colour characteristic of 
glycogen is obtained. 
Now, if the skin be macerated with strong potash solution 
and the quantity of ether-soluble substances is estimated, it 
