ELEVENTH ANNUAL MEETING. 69 
Hydra, Spongilla, etc., were proved to be truly vegetating ani- 
mals.”’ While some organisms, like the foregoing, appear to have 
true chlorophyll grains imbedded superficially in their own sub- 
stance, others, like the radiolarians, some siphonophores, sea- 
anemones and jelly-fishes, harbor true vegetable parasites, or 
preferably, vegetable guests. 
That the green observed in a number of animal organisms is 
of the nature of chlorophyll, or leaf green, has been proved by 
Lankester by means-of the spectroscope. A. W. Bennett, in al- 
luding to Lankester’s observations, says: “In all cases the 
chlorophylloid substance agrees in having a strong absorption 
band in the red—a little to the right or left—and, except in /do- 
tea, in being soluble in alcohol, and in having strong red fluor- 
escence, and in finally losing its color when dissolved.” 
The vegetable organisms which have been found to inhabit 
the lower forms of life alluded to in the foregoing paper have 
been regarded as belonging to two genera, which Dr. Brandt 
has named Zodchlorella and Zodxanthella, and which are probably 
in part synonymous with the genus /PAz/ozoon, afterwards pro- 
posed by Mr. Geddes. The latter gentleman, however, claims 
to have first demonstrated the truth of the view that the yellow 
cells of radiolarians and polypes are alge ; secondly, the found- 
ation of the hypothesis of the Jichenoid nature of the alliance 
between alge and animal into a theory of mutual dependence ; 
and thirdly, the transference of that view from the region of 
probable speculation into that of experimental science. 
Hitherto apparently no one has noticed the occurrence of 
green vegetable parasites in bivalve mollusks except Prof. 
Leidy, who has very kindly permitted me to use the facts ob- 
served by him relating to Axodon, one of our common fresh- 
water mussels. In this animal he some years ago observed what 
must be considered to be algous parasites. He found them in 
great numbers infesting the tissues of the mussel and of a larger 
size than the nuclei of the cells of the host, in which they were 
embedded. They were also provided with a nucleus, and were, 
therefore, not a part of the animal, but a distinct vegetable or- 
ganism, These facts observed a long time since, render it very 
