Physiology of same Zoophytes. 399 
the cilia were acting very languidly. I saw another while swim- 
ming about become entangled by its cilia to the sete projecting 
from the body of a small annelide. During the movements of 
the annelide, the hairs on the prolonged anterior extremity came 
in contact with some small fragments of sea-weed, and the an- 
nelide after some struggles detached itself from the ovum, which 
continued to adhere to the sea-weed. In all of these I never 
observed the least movement of the hairs attached to the anterior 
extremity. I was not able to ascertain that the smaller portion 
of the ovum left in the capsule underwent any change, as I pre- 
sume it does, before it escaped from its interior. Several bodies, 
having one portion of their surface ragged and devoid of cilia, 
and in every other respect resembling the smaller portion of the 
ovum, and also other bodies exactly similar to the entire ovum, 
were observed swimming about; but as in all these cases the 
portions of the polypidom had been injured immediately before, 
and some of the ovary-capsules broken, it was presumed that 
these had been mechanically displaced from the capsules. The 
larger portions of the ova were, like the entire ova, composed of 
minute nucleated cells, and did not, as far as I could discover, 
possess any internal cavity. 
In several specimens of Cellularia reptans and C. seruposa, and 
one specimen of C. avicularis procured at the same time, the 
ovary-capsules were filled with ova; in the two former of a deep 
orange colour, composed of nucleated cells, having the same 
number and arrangement of membranes and provided with cilia 
as in Flustra avicularis. Some of these ova were in rapid rota- 
tory motion; others, as in Flustra avicularis, were motionless, 
though the cilia were acting, being kept quiescent by the more 
close apposition of the inclosmg membrane. I did not succeed 
in observing the escape of any of these ova from their vapsules. 
In many of the polype-cells of all of the above-mentioned 
polypes, dark ved bodies composed of nucleated cells inclosed in 
a membrane were present. These nucleated cells are generally 
considerably larger than those entering into the formation of 
the ova in the ovary-capsules. The greater number of polype- 
cells contained one only of these bodies, and it was connected 
to the inner surface of the cell by a membrane having a num- 
ber of detached nucleated cells of a light colour adhering to it. 
These bodies occupied different positions between the bottom 
and aperture of the cells, but in none were distinct ciliary mo- 
tions observed. These bodies are also probably ova, and it is 
possible that more extended observations may enable us to de- 
tect cilia on their surface at a more advanced stage of develop- 
ment, though none in the present case were seen even on those 
lying at the aperture of the polype-cells. I have satisfied my- 
