60 
little chain of eggs of thiskind, which the vul- 
gar thought dropped down from heaven, and 
therefore immediately framed a great many 
fuperftitious fables concerning it: fo far is ig- 
norance the mother of error. ‘The tefticles, 
after coition, are found deprived of their fperm. 
The blind appendage of the uterus likewife, 
in the beginning, though not very much, be- 
came afterwards contra¢ted, and had thrown 
off its bone. The common tube between the 
penis and uterus fuffered no change. ‘The vas 
deferens was more dilated, and in it, as I have 
faid, I found the little bone. Hence it is pro- 
bable, that this little bone, at the time of coi- 
tion, carries fome of the fpermatic humour 
The BO O-K: of N ATU R Esso, 
through the upper tube of the vas deferens into 
the uterus; whilft the penis, in the mean time, 
throws its fperm from the inward part into it. 
To conclude, the little part in the form of a 
chain had undergone no change, unlefs that on 
the fide near the fpiral convolution of the liver, 
the veffels that it diftributed there, were here 
and there very unequally dilated and filled with 
a calcarious humour; except that fome little 
round whitifh membranes, which appear per- 
forated inthe middle, and marked with a black 
{pot, were here and there obferved fluctuating 
in its hollow canals, which refemble the leaves 
of trees. 
CP ra ok Pe Xe 
Of the brain and nerves, and in what manner thofe parts have their mufcles, 
whereby they are moved backward and forward in the body; a wonderful 
particular not hitherto known in any animal. . 
[i is with very great difficulty that any cer- 
tain and fixed place can be affigned to the 
brain of the Snail, as I have obferved in the 
beginning of this account; fince, like other 
parts, it has its mufcles, whereby it is fometimes 
drawn forward, and fometimes backward inthe 
body. This motion of the brain is fo wondet- 
ful in this little creature, that it deferves the 
mott ferious confideration. Since I have never 
hitherto, nor do I know, that any other has, 
obferved any thing like it in any kind of ani- 
nimal; I fhall, for that reafon, minutely de- 
{cribe the brain, and reprefent it by a figure, as 
I have feen it in a Snail, which I killed flowly 
under water. The brain is placed upon the 
ftomach itfelf, which, together with its gullet, 
always paffes through the aperture which the 
brain forms there. And this is not peculiar to 
Snails only, it holds likewife in Silkworms, and 
in all other infects that I have hitherto exa- 
mined. Hence it is, that when the ftomach, 
with the gullet, and all parts of the mouth, are 
drawn up on the outfide, or down on the in- 
fide ; the brain being always placed upon the 
{tomach, is transferred hither and thither with 
it. Since therefore all parts of the mouth 
may be, according to the diffection of the brain 
before-mentioned, drawn forward and pufhed 
out; I fhall, in the firft place, expofe to view 
all the parts of the jaws, mouth, and palate, 
Tab. VI. fig. 1. a. Left the ftomach and its 
oefophagus {hould interfere in my giving a full 
and exact reprefentation of the brain and 
nerves, as they really are, I cut the ftomach 
about the gulletd, by which means the brain 
is feen immediately. 
like little globes, and is therefore divided into 
two parts: from each of thefe globes arife a 
certain part of the fpinal marrow, refembling 
on each fide a large nerve dd, both which parts 
are fituated in fuch a manner as to leave a gap 
or aperture for the paflage of the ftomach. 
It confifts of two parts 
Thefe parts, {pringing from the brain, confti- 
tute the true principle or rudiments of the {pi- 
nal marrow, and they meet again a little lower, 
and form a confiderable knot, Tab. VI. fig. 1. e; 
from which, afterwards, arife all the reft of the 
nerves that are diftributed in the lower part of 
the body. There we are to obferve, that the 
{pinal marrow is double, not only in this crea- 
ture, but alfo in man himfelf, and in quadru- 
pedes; with this difference only, that in the 
latter it is prefently joined together by a certain 
intervening band, and immediately after inclofed 
in a common membrane. Nay, all the nerves 
in the latter, that arife from the marrow, form, 
each in its courfe, certain little knots or {wel- 
lings, which are therefore at leaft more nu- 
merous there. The fame is feen in Silkworms, 
in which the two originations of the fpinal 
marrow are many times tied. | 
This {welling of the fpinal marrow in the 
Snail has its mufcles likewife, by the help of 
which it is moved up and down in the body. 
Its firft mufcle is very fmall 4 arifing froma 
coat which covers the {welling or production : 
from thence, paffing under the ftomach and 
brain, is at length inferted by itstendon, in the 
lower region of the parts of the mouth, a little 
above the root of the tongue; therefore it can 
move this little knot and the brain towards the 
fore parts. The reft of its mufcles, which 
draw it back again to the hinder parts, are 
common to the inward lips; for the mufcles of 
the latter run on each. fide over this fwelling, 
and fix fome of their tendons therein, though 
they are otherwife inferted in the horny fub- 
ftance of the Snail. After thefe mufcles have 
paffed over the fwelling or production of the 
{pinal marrow, they acquire a little nerve from 
that part which gives them the power of con- 
traction. To avoid confufion, I have here exhi- 
bited only a fmall part g of thefe mufcles, with. 
their little nerve, which is afterwards extended 
further 
