NOTES ON OLIGOCHATES. ay) 
have been able to examine, the oval corpuscles are relatively 
about as abundant as in the adult; but the free ones appear 
to be more rounded and flattened, and with fewer granules, 
thus resembling what I have taken for the younger stages in 
the adult. As no definite signs of extensive disintegration of 
the corpuscles are apparent, and as I have never observed any 
case of their multiplication by division, it would seem that the 
life of each individual corpuscle must be of considerable 
length, and that they are but rarely renewed. 
The third and most interesting kind of ceelomic corpuscle 
should probably be reckoned as a variety of that just described. 
The body of the cell, though smaller, is formed of a similar 
meshwork, enclosing granules of identical appearance and pro- 
perties ; the nucleus also resembles that of the ordinary oval 
corpuscle (n., fig. 12), but lying on one side is a colourless 
refringent body of peculiar structure. This body, in the 
fully developed form, is of the shape of a thick disc or of a 
truncated cone, thicker at the edge than in the centre (thr., 
figs. 12—15), the flat surface being next to the nucleus. 
When the celomic corpuscles are squeezed out of the worm 
under a cover-glass, and they come into contact with some 
strange fluid, such as distilled water, or even salt solution, it 
becomes apparent that the refringent body is formed of a 
long thread of transparent homogeneous substance, 
closely coiled like a rope (fig. 13). Surrounded by a thin layer 
of protoplasm the thread-coil is obviously an endoplastic pro- 
duct of the ccelomic corpuscle. At first I took these strange 
bodies for parasites, but subsequent observations have proved 
this view to be false. 
As already mentioned, immediately the corpuscle comes 
into contact with some foreign liquid, such as distilled water, 
weak acids, or alkalies, the body of the cell begins to dis- 
integrate, the coil of thread swells and gradually unwinds, 
forming a tangle of loops, amongst which I have never de- 
tected free ends (fig. 13). The thread appears to be thicker 
in some places than in others, or perhaps it would be more 
correct to say that the coils stick together in certain regions, 
