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GUY 0. ROBSON. 
and stored in the ovary at sexual maturity, and that the 
presence of this substance circulating in the blood acted 
as a stimulus for the production of the secondary sexual 
characters. 
The chief evidence upon which this theory was founded 
was that the roots of the Sacculina can be seen taking 
up from the blood of the crab a fatty pigmented yolk 
material of the same micro-chemical nature as that which is 
normally deposited in the ovary of the mature female crab. 
Mr. Smith adduced no evidence at the time to define the 
origin of this substance, but the chance perusal by him 
of a paper by Heim (3) on the blood of Decapod 
Crustacea suggested a means of procuring such evidence. 
Heim had observed that the freshly drawn blood of certain 
Decapoda (Maia, Homarus, Portunus and Astacus), is 
periodically charged with a pink or a yellow colouring 
matter (lipochrome). He came to the conclusion that this 
colouring matter is present only in the blood of the female, 
at the time when the ovary is maturing. He suggests that 
the lipochrome is formed in the liver and transferred thence 
by the blood to the ovary. Since lipochromes in general are 
soluble in fatty substances and are invariably found associated 
with them, it is obvious that Heim’s observations have an 
important bearing upon the theory recapitulated above. It 
shows that at the period of sexual maturity in the female there 
is circulating in the blood a fatty material which is prob- 
ably transferred thence to the ovary. It seemed to suggest 
that if the theory as to the effect of the Sacculina were true, 
we might possibly find such a lipochrome in the blood of 
sacculinised crabs of both sexes. The evidence I have 
collected as a result of these investigations, on the whole, 
seems to support Mr. Smith’s theory, though the occurrence 
of the lipochrome in Inachus does not follow the simple and 
diagrammatic rule laid down by Heim for the animals upon 
which he worked. 
The subject was suggested to me by Mr. Smith, and 
I wish to take this opportunity of expressing my gratitude 
