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 



