56 
Williamson on Volvox globator. 
doubtless resides in all. The cell-walls in the Volvox re- 
semble the cells in which the Confervoid Zoospores are deve- 
loped, the only essential difference being, that in the former 
instance the cilia penetrate the cell-wall, instead of being 
retained within it, and the germination is carried on whilst 
the Zoospores maintain their connexion with the parent 
sphere, instead of being previously detached from it. 
All the facts brought to light by this inquiry confirm my 
previous conclusion (which conclusion receives, also, the 
effective support of Mr. Busk), that the affinities of Volvox 
are with the vegetable, and not with the animal kingdom. 
Since the above memoh- was laid before the Society, Mr. Busk has 
supplied me with specimens of Volvox stellatus. I quite agree with him 
in his view that V. stellatus, V. glohator, and V. aureus are mere varieties 
of one species. In his specimens of V. stellatus the protoplasms were of 
the stellate form of fig. 1. The investing cells were obviously present in 
all the examples which I examined. The above generalisation by Mr. Busk 
does away with the possibility of the brilliant granules of the protoplasm 
being spores, and leads to the probability that the curious bodies either 
in V. stellatus or V. aureus are the true winter spores. In V. stellatus I 
have noticed that the ordinary power of gemmation appears to have worn 
itself out; since, though the gemmee often co-exist with the spores (?), 
they are small, colourless, and abortive. The curious stellate invest- 
ments of the spores (?) of V. stellatus appear to me to be homologous 
with my vesicles (fig. 5 /), within which the true gemma? are developed, 
and consequently to be the modified primary germ-cells. These often exist 
without the stellate protuberances, when their resemblance to the vesicles 
of the gemmte is very obvious. In the pond from which I chiefly obtained 
my specimens this year^, they were all of the type represented in fig. 10. 
This was their character in April. In the beginning of September, all 
traces of the connecting threads had disappeared, each protoplasm then 
resembling my fig. 4. At the close of September nearly all the Yolvoces 
disappeared. In the few that remained, the protoplasms had reverted to 
the stellate type of fig. 1. 
