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far the smaller one of the two, contained a bright orange- 
coloured substance, which, on examination with the higher 
powers of the microscope, was found to consist of incalculable 
numbers of spermatozoons, either clustered together, or in- 
dependent of each other, as shown at fig. 4. The anterior 
chamber, at this stage, exhibited no trace of an opening of 
any kind; but from the posterior portion of the smaller one 
a tubular passage proceeded downwards and backwards, 
terminating in an orifice at 0. 
After floating about for a greater or less time in the con- 
dition just described, a sudden change took place, and the 
wall of the anterior chamber giving way, the enclosed ova 
were discharged with some amount of force into the sur- 
rounding medium, the appearance then presented by the 
organism resembling that shown at fig. 3, the letter a@ indi- 
cating the irregularly outlined aperture through which the 
ova had burst their way. In this last condition I find it 
impossible to disassociate it from the form first described 
under the name of Appendicularia flagellum, by Chamiso, 
since productive of material for elaborate memoirs by 
Professor Huxley, Leuckart, Gegenbaur, and other eminent 
authorities, and if not identical with it, it is certainly a very 
closely allied species. Assuming this, it would appear evident 
that these singular organisms have been hitherto observed 
and described only under one phase of their existence, and 
that subsequent to the discharge of the most important 
function they are destined to fulfil. Professor Huxley’s 
remarks on the “crumpled and wrinkled” condition of the 
body, the ill-defined edges of the anterior portion, and his 
inability to detect any other than spermatic reproductive 
elements, recorded in the ‘ Philosophical Transactions’ for 
1851, and further confirmed in the volume of this Journal for 
1856, of themselves indicate the collapse succeeding the 
discharge of the ova had already taken place when he 
examined them. 
I may add that the ova on their release were perfectly 
transparent, and presented no trace of cleavage or differentia- 
tion of any kind, and hence we may justly infer impregnation 
is effected in the water after their expulsion, and not neces- 
sarily from the spermatic elements contained in the same 
capsule. The discharge of the spermatozoons from the 
smaller chamber is by no means so sudden or complete, a 
large portion of them remaining within, and imparting to it 
the orange tint already noticed, long after the ova have been 
released. 
At this stage the ciliary action observed by other writers 
