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The 
pertains to it; the twelve upper branchie or 
gills, the ten lower oars that ferve the creature 
for f{wimming, the tails with their appendages, 
and laftly, the apertures of the pulmonary 
tubes under the breait. 
The inward parts of the male are, befides 
the blood and membranes, mufcles and fat, the 
ftomach and inteftines, the pulmonary tubes, 
the heart, the fpinal marrow, and the {permatic 
veffels. 
In the female I find all the parts juft recited, 
with only this difference, that inftead of fper- 
matic veflels an ovary is here feen, furrounded 
with {mall membranes, which are interwoven 
with very many pulmonary tubes. 
As Ihave not yet accurately examined the 
internal parts of the head and eyes, for want 
of a fufficient numbér of Worms and Flies, 
I fhall not fay much concerning them, nor of 
the parts of the thorax, the latter being for 
the moft part filled with the mufcles of the 
legs and wings. ' 
If the male Worm of the Ephemerus, which 
it is eafy to diftinguifh from the bignefs of its 
eyes, be firft laid on its back ona {mall piece 
of a fir board, and then faftened with the 
fmalleft needles that can be had on black paper 
or a {mall piece of linen, we immediately fee 
a thin and watry humour diftilling out of the 
wounds in the skin, which is the real blood of 
this infect. And yet it is not red, as is the 
eafe in Earth-worms, the blood of which, as 
well as that of quadrupedes, is tinged with that 
colour. I don’t know a more proper inftru- 
ment to open the {kin than a fine and {mall 
pair of fciffors, for little lancets, though never 
fo fharp, are not fit for this purpofe, becaufe 
they always pull and tear the parts afunder, 
and efpecially if the membranes be not equally 
hard. 
When the skin is after this gently and deli- 
berately feparated with a fine fharp-pointed 
pen-knife from the parts underneath, an inte- 
rior very thin and membranous skin immedi- 
ately appears. If this be afterwards cautioufly 
removed, the mufcles of the belly prefent them- 
felves to view, as well thofe which extend 
from one divifion to another, with ftraight 
fibres of the body, as thofe which are pro- 
tended obliquely and acrofs: other mufcles are 
alfo feen, which ferve to move the branchie 
or gills. The coat or other {kin is likewife 
fibrous, and {eems to be joined to the mufcles 
before de{cribed. 
After the mufcles appears a very fine and 
delicate membrane affixed to them, which I 
take to be the peritoneum. About and under 
this appears a quantity of fat, confifting of 
fmall, fine, and white veficles, which contain 
a real fat in the form of fluid oyl, Whoever 
views thefe veficles without a microfcope, may 
naturally take them for. the fat itfelf, whereas 
they are only thin and very tender bags con- 
taining it, as is the cafe in man and other ani- 
mals. This will be very plain, if thefe pingue- 
ferous bags, which are of equal bignefs, be 
Bb SvTy Oy Rey 
of INSECTS: 
viewed with a microfcope. The younger the 
creatures are, the more confpicuoufly they ex- 
hibit this fat, fince it then lies here and there 
difperfed on the membranes, nor is it heaped 
together fo thick as in the older ones. 
After obferving thefe, we come to the fto- 
mach, Tab. XV. fig. v. and to the inteftines 
which are continued fromit. Here is prefented 
to view the cefophagus, or otherwife the tube 
of the upper orifice of -the ftomach, which 
defcends like a fine filament from the mouth 
or jaws through the back and thorax, and 
enters and is connected with the upper part of 
the ftomach. Where this little tube is con- 
nected with the ftomach, it becomes narrower 
and cloffer a, as may be feen about the lower part 
of the ftomach, or towards its lower orifice 4. 
Though the ftomach ¢ confifts of divers 
parts, yet.it feems throughout to be formed of 
a thin and tender membrane, corrugated on the 
infide, and full of reticulated or net-like folds 
or plaits. On the outfide it exhibits a f{mooth 
furface, and is expanded regularly, efpecially 
when it is {wollen or filled with food, or if it 
be artificially diftended with air, by the help of 
a {mall glafs tube. -No veins or arteries are 
feen in it, for the blood of thefe infects is of a 
watry colour, and therefore does not diftinguifh 
the veffels containing it from the other parts ; 
this is the reafon that thefe creatures were called 
exanguious or without blood. 
It is however obferved, that the ftomach ¢ 
is provided with many tubes which refemble 
blood-veffels. But if they be well examined 
with a microfcope, it appears they are branches 
of the pulmonary pipes, Tab. XIV. fig. 1. aa, 
for they give little air canals, not only to the 
{tomach but to all the external as well as inter- 
nal parts of the body. Hence, even the legs 
and their claws have air tubes. The inteftines, 
Tab. XV. fig. v. joined to the under part of 
the ftomach, appear to be threefold in regard 
to their form ‘and ftructure: there appear, ift, 
the crooked or fmall gut dd; then 2d, the 
colon ¢; and laft, the retum f. Within the 
{mall gut, fomewhat further towards the hinder 
parts, are obferved fome lunated wrinkles, not 
unlike thofe little vales of the fmall guts in the 
human fpecies, which the anatomitts call annu- 
lares. A little below where the colon e, rifes out 
of the former, are feen feveral oblong furrows, 
which are very fine in the living creature, and 
refemble fo many long mufcular villi or hairy 
parts extended in the cavity of the inteftine, 
correfponding in fome meafure with the echi- 
nus, which isa natural part of the ftomach 
of quadrupedes: then the rectum follows 
this, and is folded very elegantly, until it ter- 
minates at the external parts of the body with 
a pretty large orifice, through which the feeces 
are difcharged. 
The ftomach ¢ is fituated between the fourth 
and fifth annular divifions of the body, and 
there, together with the fmall gut, takes up 
the whole foremoft region of the belly, that is, 
the 6, 7, 8, 9, 10, and 11th incifions. But 
joy the 
10g 
