lp eS 
ihe Et 8. FOR. Y fof (NS Sahec. Ts: 
tonfiruGion of fome of the internal parts, 
which I have here alfo delineated. ‘The genital 
organs are thruft out of the neck, in the fame 
manner as in the houfe Snail, and are found to 
be likewife placed behind the parts of the pa- 
lateand mouth, Tab. IX. fig. 11. a. On each. 
fide the larger horns 64 may be feen when 
drawn in; they appear under the divided skin 
of the head. Behind the proper parts of the 
mouth, and above the gullet ¢, is placed the 
brain e, which is formed of two {mall parts 
like globes, applied clofe to each other: Im- 
mediately after appears the origin f of the fto- 
mach, together with the falival vefiels gg, 
which are here reprefented as clipt or cut off 
near the gullet. After thefe are obferved two 
glandular corpufcles £4; from which the falival 
veflels arife. Then at length is prefented to 
our view the ftomach, with its veflels 2, which 
are of a pure white, like the colour obferved 
in the inteftines 2&4. The windings of the in- 
teftines furround the liver ///, which confifts of 
{mall glandules, equally divided and interwoven 
with very white veffels. It fends forth the 
gall-bag m, which is large, and difcharges itfelf 
into the {mall guts that are next to the fto- 
mach. 
The beginning or rather end of the genital 
organs is feen in the skin # of the neck, and 
their mouth or opening appears there in the out- 
ward skin; which, however, I have not exhi- 
bited in this place, that the other parts might be 
the more diftinlly vifible. The firft thing that 
prefents itfelfis the peniso, which, being twifted 
like a tendril of a vine, opens with a kind of 
tube p into the cavity of the uterus. Nothing 
of this kind is obferved in the houfe Snail; but 
in the covered Snail there is likewife a common 
duct, and the penis is extended longer. Behind 
the penis is feen a remarkable pear={haped bagg: 
this is the purple-bearing bag; it is very large 
in this Snail, and contains a delicate juice. It 
opens by a {mall tube 7 into the cavity of the 
skin of the penis, by means of which the latter 
erects itfelf, 
The origination s of the uterus is pretty thick 
and {trong, and after it grows fmaller ¢, it 
GiB Ss Recs 
73 
twifts and bends itfelf, and goes into the body 
of the uterus wuuu, as it does in many other 
Snails. But the ligament of the uterus is not 
feen in this; its place is occupied by feveral 
whitifh vefiels, which are connected xxx by a 
{mall kind of membrane, that ties the curled 
windings of the uterus. About the end of the 
uterus, where the bag of glutinous moifture yy 
is joined to it, is feen a place where the chain- 
like tube is inferted, or fixed in the uterus - 
nay, it further appears, how this tube runs 
through and over the liver, and under the {mall 
guts, and is connected with the ovary &, 
which is here empty. This ovary is divided 
into two parts, as it isin other creatures. The 
divifion, however, is not fo remarkable in thofe 
Snails; which have not exercifed venery, as it 
isin the ovary, which I. here exhibit alone, 
fig. t11. a. I therefore reprefent this ovary big 
and expanded, as I think I faw it fome months 
after coition. For it is then obferved, that this 
little part confiderably increafes, Tab. IX. fig. 
111, a; and that the eggs 54 are made vifible 
therein. Ihave likewife obferved this increafe 
in the ovary of the fhelly Snail. But the eggs, it 
feems, are afterwards difcharged out of the 
ovary, and defcend through the chain-like lit= 
tle tube ¢ into the cavity of the uterus, to the 
hinder part of which the former is joined, fe; 
11.2. But as the paflage of the eggs is fo 
near to the bag of glutinous humour, I there- 
fore think, they are there covered over with a 
little of it, and that when they grow larger, they 
get more of it, and, at length, attain their full 
bignefs in the uterus. But I could never hi- 
therto find eggs in the chain-like little part, as I 
have already mentioned in the defcription of 
the houfe Snail ; nor could I fee that they are 
conveyed through it. I thall therefore defer 
advaneing this opinion as an undoubted truth 
until I fee it myfelf; though I think, at the 
fame time, the matter may moft probably hap- 
pen fo. The heart likewife is feen in its na- 
tural fituation y, as alfo the manner in which it 
is {urrounded by the bag S¢ of calearious or limy 
matter. 
P, XIV: 
Of the common water Snail, alfo, of an uncommon and viviparous kind of water 
Snail; and of the flatted water Snail, and the wmufcles of the river echt. 
Ajo a remarkable obfervation on the common Snail, 
Hi E common water Snail, which I find 
every where at the edges of ditches in 
Holland, differs much both from the common 
covered, and from all other Snails. It is di- 
ftinguifhable, not only in regard to the outward 
skin or fhell, but alfo with refpe& to its eyes, 
and the apertures both of the verge and the 
genital organs, which are all con{picuous on the 
outfide. There is alfo a ftill greater difference 
in the internal parts ; all which I fhall now 
briefly enumerate. 
The fhell, which is in the form of a fphe- 
roid in the large Snail, is in the water Snail 
rolled in an oblong form like that of the Tur- 
bo, Tab, IX. fig. 1v. a. But there is ftill a 
greater difference in its eyes; for as the latter 
in the common Snail are at the ends of the 
horns ; on the contrary, they are found in this 
aquatic 
