62 
The ova vary in number. I have occasionally found but a single 
one in each sporosac, though most usually from three to eight. 
They present the germinal vesicle and germinal spot, and may be 
observed to undergo segmentation. 
The ciliated embryo is of the usual conical form. When about 
to change to the fixed state it attaches itself by one extremity, 
which becomes extended in the form of a four-lobed star, resembling 
a Maltese cross, from whose centre rises perpendicularly the pri- 
mordial stem of the future zoophyte, at first in the form of a small 
cylindrical process, which elongates itself more and more, becoming 
at the same time invested with a delicate polypary. 
We next find that on one side of the young stem a cell is formed 
in which the coenosarc becomes developed into a polype. 
Beyond this point I had no opportunity of observing the progress 
of development. 
I have found the male gonophores on the same stem with the 
female, so that here the usual dioecious condition is departed from. 
The male gonophores are smaller and much less numerous than the 
female. The manubrium is less distinctly lobed, and is surrounded 
by a mass of spermatozoa instead of ova. The spermatozoa consist 
of a minute, somewhat pyramidal, body about 3V00 an i n °h 
diameter, with a caudal filament. They are developed in vesicles of 
evolutions, from which they seem to be produced by a transforma- 
tion of the nucleus. 
I obtained the Plumularia pinnata in abundance with the repro- 
ductive capsules, during the months of September and October, in 
rock pools near low-water mark at Lisnaleen. 
Plumularia cristata. 
Plumularia cristata is very remarkable, by a singular arrangement 
destined for the protection of its gonophores. 
These are borne on certain peculiarly metamorphosed ramuli^ 
which we must be careful not to confound, as has hitherto been done, 
with the proper gonophores of other zoophytes, and for which, be- 
lieving it therefore necessary to give them a special name, I pro- 
pose the term corbulcc , suggested by their basket-like form. In 
these corbulse the proper gonophores are contained. The peculiar 
metamorphosis of the ramulus, which results in the formation of 
a corbula, consists in its developing from its sides alternate leaflets, 
