385 
of Edinburgh, Session 1881 - 82 . 
digested ; the yellow masses supposed by various observers to be 
developing cells, being sometimes, no doubt, Tintinnoids in process 
of digestion, as supposed by Cienkowski, but much more frequently 
specimens of Philozoon in progress of solution and disappearance. 
Again, the animal cell is constantly producing carbonic acid and 
nitrogenous waste, but these are the first necessities of life to our 
alga, which removes them, so performing an intracellular renal 
function, and, of course, reaping an abundant reward, as its rapid 
rate of multiplication shows. 
Nor do the services of the Philozoon end here, for during sunlight 
it is constantly evolving nascent oxygen directly into the surrounding 
animal protoplasm, and thus we have actually foreign vegetable 
chlorophyll performing the respiratory functions of native animal 
haemoglobin. And the resemblance becomes closer when we bear 
in mind that it has been shown that haemoglobin frequently lies as 
a stationary deposit in certain tissues like the tongue muscles of 
certain molluscs,* and the nerve-cord of Aphrodite and Nemerteans. 
The importance of this respiratory function is well shown by 
comparing specimens of the common red and white Gorgonia , 
which are usually considered as being mere varieties of the same 
species, G. verrucosa. The red variety is absolutely free from 
algae, which of course could not exist in such deeply coloured light, 
while the white variety, which I am inclined to think usually the 
commoner, larger, and better grown of the two, is perfectly crammed. 
J ust as with the anemones above referred to, the red variety evolves 
no oxygen in sunlight, while the white yields abundance, and we 
have thus two widely contrasted physiological varieties , as we may 
call them, without the least morphological difference. The white 
specimen, placed in spirit, yields a strong solution of chlorophyll ; 
the red again gives a red solution, which was recognised as contain- 
ing “ tetronerythrin ” by my friend M. Merejkowsky, who was at the 
same time and place investigating the distribution and properties 
of that remarkable pigment, so widely distributed in the animal 
kingdom. This substance, which was first discovered in the red 
patches which decorate the neck and head of many birds, has 
recently been shown by Krukenbergf to be one of the most 
* Lankester, Brit. Ass., 1871, p. 140. 
t Vergleich. Physiol. Studien, Bd. I. Abth. 2. 
