VI COLOURS OF CRUSTACEA AND ECHINODERMA 127 
Green colouring - matters occur sometimes in the 
shells of various Crustacea, but also very commonly 
in the eggs both of shallow and deep water forms. 
The ovarian eggs of the lobster are a bright green, 
while the extruded eggs are a dark green. Both 
yield a turbid green solution to water, which clears 
up at once on the addition of ammonium chloride, 
probably because this dissolves up proteid. If the 
clear green solution be allowed to stand, it some¬ 
times deposits orange-coloured drops of oil and then 
becomes a clear blue. The blue solution gives all 
the characters of that obtained from the carapace. 
There is therefore reason to believe that the green 
colour of the eggs is due to a combination of the 
blue lipochrome compound found in the shell and a 
yellow pigment dissolved in fat. The association 
of this yellow pigment with yolk in eggs is, of 
course, exceedingly common. 
An interesting confirmation of the view here 
propounded as to the origin of the green colour 
of lobsters’ eggs is found in an observation by Mr. 
Chiyomatsu Ishikawa. In studying the develop¬ 
ment of Atyephira compressa, this author noticed 
that the ova in the very young stages were pale 
blue, but as the yolk developed they became green. 
It would thus seem that we are justified in saying 
that the green pigments of Crustacea are at least 
in some cases produced by a mixture of the blue 
lipochrome compound and a yellow pigment. From 
the changes which the shell of the lobster undergoes 
as the blue colouring - matter is removed, I am 
further inclined to believe that the brown colours 
which are not uncommon in the group are similarly 
