On the Green Colouring Matter of Animals, and Recent 
Researches in Symbiosis. By Auten Harker, F.L.S. 
Read 12th December, 1882. 
My object in bringing this very interesting question before 
the Club is to place on record some few observations, and 
experiments bearing upon it, which have been made, firstly, by 
my friend Mr W. H. Hottanp, partly at my suggestion, and 
secondly, by myself, in the Biological Laboratory of the Royal 
Agricultural College. 
It has long been known that the bright green colouring 
matter of plants which, though composed of several distinct 
colouring matters, is called collectively Chlorophyll, is not 
confined to the Vegetable Kingdom, but occurs also in certain 
Animals. PrissttEy is said to have obtained oxygen from 
Euglena viridis, whence it was argued that Huglenz were plants; 
but the first accurate observations were made by Max Scuuntze 
on a green coloured Rhabdocele Turbellarian, Vortex viridis. 
I shall refer again presently to this worm in connection with 
some of my own observations. The list of animals which do 
contain this colouring matter is gradually being enlarged as 
our knowledge of the minute forms of life extends. Ray 
LanxesTER has recently given a list (Q. J. M.S., 1879) of all in 
which it had been detected up to that date. This list includes 
an Infusorian, Stentor Miilleri, several Radiolaria, Spongilla, 
Hydra, Anthea, several worms, and a Crustacean. 
In some of these the colouring matter is localized in con- 
spicuous granules, in others in much finer granules, while in a 
third group it is apparently diffused. 
To this list it seems not unlikely that many Infusoria will 
be added when they have been obtained in sufficient numbers 
to give reliable results. I propose to add Euglena viridis to the 
list, probably several other species, if not all the members of 
