The BOOK of 
lected, when they pafs through the cornea, 
though this isnotimprobable. If one removes 
the uvea, by means of water and a fine pencil, 
from out of the inward cavity of the cornea ; 
this latter becomes then all bright and clearly 
tran{parent. 
After the uvea follows a matter or fub- 
ftance like glue; it is fomewhat vifcid, but 
thin, and divides itfelf into very tine filaments, 
Tab. XXIX. fig. vir.a: thefe may be taken 
for inverted pyramidal fibres. When the cor- 
nea tunica 1s removed from thefe filaments, 
blackith {pots are feen on the eye, which are 
the remains of the uvea ftill flicking there; 
for the pyramidal fibres are by means of the 
uvea connected with or joined to the {pherical 
apertures of the cornea.. All thefe fibres ter- 
minate in a thick, fibrous, and inexpreffibly 
white tunic or coat, Tab. XXIX. fig. viz. 4; 
the fubftance of this, however, is of a darker 
colour d, where it is united to the optic nerve 
which is here feparated c. Many pulmonary 
tubes likewife run up and down here, which 
ftrongly. connect that coat with the optic nerve, 
which it receives: thefe air-pipes pafs alfo 
through that white fibrous coat we have de- 
{cribed, and are conveyed e¢ along the inverted 
pyramidal fibres, reaching to the cornea itfelf 
in form of very delicate ramifications ; and in 
my opinion form the hexagonal divifions of 
the eye. Here at length may be conceived, 
in what manner the eye, whilft the exuvia or 
skin is cafting, acquires its extenfion, form, 
and roundnefs by the help of the internally 
impelled air and blood. The roots of thefe 
pulmonary tubes are found to be fituated un- 
der. the optic nerve, where they firft provide 
for the coat, wherewith that delicate nerve is 
invefted ; and thus, with a confiderable rami- 
fication adhering underneath, is alfo fur- 
rounded with or accompanied by fuch air- 
tubes. 
But we mutt here take particular notice that 
thefe eyes are, in each fide of the head, di- 
vided as it were into two parts, fig. vi11. ff 
as I have reprefented in-a particular figure, 
wherein is likewife exhibited g the horn of 
the head.. This divifion is produced by means 
of two horny or bony prominences of the skull, 
which extend themfelves from each fide of 
the eye unto the outmoft furface thereof; 
hence it happens that the eye is in the fame 
manner divided in its internal part, fig. vi1. 4; 
fince the inward ftruture is analagous to the 
outward. ‘The optic nerve has no incifion or 
divifion, but the pyramidal fibres are wanting 
where this incifion is, becaufe they evidently 
could be of no ufe there. 
In order to. difcover thefe things accurately 
it is firft necefiary to lay the brain bare; for 
this purpofe nothing more is requifite than to 
cut off the horn, if it be a male, with a fharp 
knife, and then to raife and feparate the cra- 
nium or skull from the brain. After this, the 
brainz comes inview. This, as I have before 
ebferved, when I treated of the fpinal marrow, 
148 
NATURE; cr, 
confifts of two globes united, and is by this 
means divided into a right and left part, as is 
likewife the cafe in men and in quadrupedes. 
It is indeed very remarkable that the brain ~is 
in this Beetle furnifhed with many pulmonary 
tubes, Tab. XXIX. fig. vit. 4, which make 
a very beautiful appearance in the living ani- 
mal. Optic nerves are obferved to iffue out of 
it on each fide, which are much larger in 
the Beetle than they were before in the Worm. 
Moreover, a common kind of membrane is 
obferved there, which invefts both thefe nerves 
and the brain itfelf, and is fufficiently thick 
and ftrong: this may be properly called the 
dura mater. Numerous air-pipes run through 
this membrane, and interweave it as it were 
with one another, fo that you would fay this 
dura matter, when feparated from the brain, 
is like an admirably beautiful net. The op- 
tic nerves are very flender where they iffue 
from the brain //; but they are confiderably 
dilated 7m a little after, and then again they 
grow {mall zz, until at length they are {wollen 
again where they approach to the inward com- 
pages or reticulations of the eye o. In that 
part thefe nerves are enclofed and furrounded 
by the interior parts of the eye, and when 
greatly magnified refemble the head of a 
Dutch failor covered with a fhaggy cap, fuch 
as fea-faring perfons ufe to wear: I compare 
to thefe fhaggy hairs, thofe pyramidal fibres 
which terminate in the convexity of the white 
fibrous coat. 
It may not be improper to obferve here 
that this Beetle is very fhort fighted, or pore- 
blind. I therefore would have the reader con- 
fider the conftruGtion and difference of the 
Bee’s eye, which fees more acutely in the 
day time; for he will find that the optic nerve 
in the Bee does not come fo very near to the 
eye, nor Is in itfelf fo remarkable and confpi- 
cuous as in this Beetle. Others may reafon 
from thefe facts as they think beft; it is fufi- 
cient for me to have propofed the truth. I 
have not yet examined the eyes of the water 
Beetles, which I know can fee both in water 
and air. I have feen the pyramidal fibres of 
the eyes in Crabs and Lobfters, All water 
Snails, as well as the human fpecies, have 
three humours in their eyes, as I have de- 
f{cribed before at large. On this occafion it 
may alfo be obferved that their eyes are fome- 
times multiplied. I proceed now to the pul- 
monary tubes, which are fimple in the Worm, 
but are enlarged by the addition of bladders 
in the Beetle ftate. 
Thefe pulmonary tubes which in the Worm 
refembled the branches of trees without leaves, 
reprefent here in the Beetle a tree expanding 
its verdant and leafy braaches: and here the 
autumn and winter of the miferable life which 
this Worm leads, is now in the perfect Beetle 
ftate changed into a pleafant and lovely fpring 
and fummer; with this only difference, that 
as the leaves of the trees have a plain and 
fmooth furface, fo thefe bladder in the Beetle 
are 
