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structure may have its function largely changed to meet a 
want in the organism ; and it has yet to be proved that the 
Limicolae use their clitelli in copulation, whilst a “ capsulo- 
genous gland,” as d’Udekem termed certain internal glands, 
is wanting in many cases. Hence, I think, we cannot infer 
any very intimate or elaborate copulation from the presence 
of a clitellus. 
The Ova . — The ova appear in round masses, paired on oppo- 
site sides of the neural cord. Their appearance may be learned 
from the figures. At first only the anterior masses appear. 
Subsequently in two cases I noticed a second small pair — that 
is, a younger pair, developing posteriorly to the first pair of 
abdominal fasciculi. There was no oviduct perceptible. The 
ova floated in masses in the most mature individual I ob- 
served, in the perivisceral cavity ; one ovum had grown much 
larger than the others in the same mass, as is very usual 
among Oligochseta. The ova drawn in PI. XV, fig. 4, were 
each about - T - u 1 0 -,- , th of an inch in diameter. The ova arise in 
the protoplasmic matter surrounding the nerve-cord, by 
extension of which same matter the homogeneous blastema is 
formed from which the head and somites are produced in 
zooid- growth. The masses of ova commence as detached 
protoplasmic masses, in which arise feebly defined nuclei, 
apparently few in number at first, but increasing in distinct- 
ness till there are seven or more visible on one surface, each 
with surrounding differentiated matter. The ova so developed 
simply hang together, not supported by any framework, and 
are easily detached from their position when their growth 
has proceeded some time. The simplicity of these ovaries is 
equaled by that of the testes, in which the sac-like figure 
disappears with development, and simple masses of sperma- 
tozoa are detached in numbers from an aggregated mass, as 
they become ripe and float freely in the body cavity. The 
masses of ova and the masses of spermatozoa thus floating are 
strictly comparable. The enormously greater relative abun- 
dance of spermatozoa, as compared to ova, is very striking. 
Their mass is even far greater. What special purpose 
does this serve in the worm’s adjustment to its conditions ? 
As to how the ova escape from the body, how they are 
impregnated, how they develop, what may he the first 
appearance of a young Chaetogaster, as also the time and 
place of his debut, I have as yet not the slightest indication. 
The interesting change from larva to adult, which is paral- 
leled amongst Polychaet, but not recorded amongst Oligo- 
chaet Chaetopoda, makes one anxious to know the whole 
history of this minutest of the class. I cordially recommend 
