ON GASTEROPODA. aaa 
The first part of the oviduct, properly so called, presents 
some unequal dilatations, which seem filled with a calcareous 
matter. Its second part is manifestly augmented in all its 
dimensions, and contains a great quantity of white matter 
resembling the spawn of fish. This matter afterwards be- 
comes gelatinous, and swells considerably in water. The 
testicle appears to be still filled with a tolerable quantity of 
fluid. 
Some time after this, the embryos, detached from the ovary, 
come into this second or swelled portion of the oviduct. 
They are enveloped there in a considerable quantity of the 
matter of which we have been speaking, and which forms for 
the little animal the fluid, by the absorption of which it is 
nourished. Later, or in another part of this oviduct, is de- 
- posited an external membrane, sometimes rather calcareous, 
and then the egg is complete. After the end of about fifteen 
days these eggs are expelled. Duvernoy makes a curious 
observation respecting the manner in which these eggs are 
formed. “If we open asnail,” says he, “alittle before the 
eges are laid, we find no eggs, but some little embryos 
swimming in a very clear fluid, and exhibiting very lively 
motions. They become eggs on the road which they are 
obliged to pursue to get out.” 
The eggs of the helices are usually rounded, tolerably big, 
and of a white colour. They are at first a little glutinous, 
and especially so in the species which deposit them serzatim, 
one after another, and in the form of a chaplet. Most fre- 
quently they are deposited one by one, or in an irregular 
mass, in holes which the animal excavates in a soft earth, but 
much more usually in natural excavations, fractures more or 
less deep in the ground, in the holes of trees, rocks, or old 
walls ; in general in places where drought cannot reach them, 
and where moisture is permanent. The number of these eggs 
does not appear to be extremely considerable. 
von, I. Z, 
