378 
Proceedings of the Royal Society 
Raphid iophrys viridis, Heterophrys mijriapoda ; Ccelenterata, 
Spongilla fluviatilis , Hydra viridis , Antliea eereus, v. smaragdina ; 
Vermes, Mesostomum viride , Bonellia viridis, Clicetopterus Valen- 
ciennesii ; Crustacea, Idotea viridis. 
The main interest of the question, of course, lies in its hearing on 
the long-disputed relations between plants and animals ; for, since 
neither locomotion nor irritability are characteristic of animals, 
since many insectivorous plants habitually take in and digest solid 
food, since cellulose — that most distinctive of vegetable products — 
is practically identical with the tunicin of Ascidians, it becomes of 
the greatest interest to know whether the chlorophyll of animals, 
as believed by Claude Bernard, preserves its ordinary vegetable 
function of effecting, or at any rate aiding, the decomposition of 
carbonic anhydride in sunlight, and the synthetic production of 
starch.* For although it had long been known that Euglena 
evolved oxygen in sunlight, the animal nature of such an organism 
was thereby rendered more doubtful than ever. 
In 1878, however, while working at the zoological station of 
M. de Lacaze-Duthiers at Boscoff, I had the good fortune to find 
material for the solution of the problem in the chlorophyll-green 
Planarian ( Convoluta Schultzii, 0. Schm.), of which multitudes are 
to be found in certain localities on the coast, lying on the sand 
covered by only an inch or two of water, and apparently basking in 
the sun. It was only necessary to expose a quantity of these 
animals to direct sunlight to observe the rapid evolution of bubbles 
of gas, which, when collected and analysed, yielded from 45 to 55 
per cent, of oxygen. Both chemical and histological observations 
showed the abundant presence of starch in the green cells, and thus 
these animals, and presumably also Hydra , Spongilla, &c., were 
shown to be truly “vegetating animals.”! 
Being at Naples early in the spring of 1879, I exposed to sun- 
light such of the other reputedly chlorophyll-containing animals as 
I could obtain there, namely, Bonellia viridis and Idotea viridis, J 
* “ Certain animals ( Infusoria , Coelenterata, T urbellaria) possess chloro- 
phyll, hut there is no evidence to show what part it plays in their economy. ” 
Huxley, Anat. of Invert. Animals, 1877, p. 43. 
t “ Sur la Chlorophylle Animale,” &c., Archives de Zool. Exp., 1880, and 
Proc. Roy. Soc. Lond., 1879. 
X Ibid., Postscriptum. 
