The so-called

tethyum or ascidian has of all these animals the
most remarkable characteristics. It is the only mollusc that has its
entire body concealed within its shell, and the shell is a substance
intermediate between hide and shell, so that it cuts like a piece of
hard leather. It is attached to rocks by its shell, and is provided
with two passages placed at a distance from one another, very minute
and hard to see, whereby it admits and discharges the sea-water; for
it has no visible excretion (whereas of shell fish in general some
resemble the urchin in this matter of excretion, and others are
provided with the so-called mecon, or poppy-juice). If the animal be
opened, it is found to have, in the first place, a tendinous
membrane running round inside the shell-like substance, and within
this membrane is the flesh-like substance of the ascidian, not
resembling that in other molluscs; but this flesh, to which I now
allude, is the same in all ascidia. And this substance is attached
in two places to the membrane and the skin, obliquely; and at the
point of attachment the space is narrowed from side to side, where the
fleshy substance stretches towards the passages that lead outwards
through the shell; and here it discharges and admits food and liquid
matter, just as it would if one of the passages were a mouth and the
other an anal vent; and one of the passages is somewhat wider than the
other Inside it has a pair of cavities, one on either side, a small
partition separating them; and one of these two cavities contains
the liquid. The creature has no other organ whether motor or
sensory, nor, as was said in the case of the others, is it furnished
with any organ connected with excretion, as other shell-fish are.
The colour of the ascidian is in some cases sallow, and in other cases
red.

All urchins

are supplied with eggs, but in some of the species the
eggs are exceedingly small and unfit for food. Singularly enough,
the urchin has what we may call its head and mouth down below, and a
place for the issue of the residuum up above; (and this same
property is common to all stromboids and to limpets). For the food
on which the creature lives lies down below; consequently the mouth
has a position well adapted for getting at the food, and the excretion
is above, near to the back of the shell. The urchin has, also, five
hollow teeth inside, and in the middle of these teeth a fleshy
substance serving the office of a tongue. Next to this comes the
oesophagus, and then the stomach, divided into five parts, and
filled with excretion, all the five parts uniting at the anal vent,
where the shell is perforated for an outlet. Underneath the stomach,
in another membrane, are the so-called eggs, identical in number in
all cases, and that number is always an odd number, to wit five. Up
above, the black formations are attached to the starting-point of
the teeth, and they are bitter to the taste, and unfit for food. A
similar or at least an analogous formation is found in many animals;
as, for instance, in the tortoise, the toad, the frog, the stromboids,
and, generally, in the molluscs; but the formation varies here and
there in colour, and in all cases is altogether uneatable, or more
or less unpalatable. In reality the mouth-apparatus of the urchin is
continuous from one end to the other, but to outward appearance it
is not so, but looks like a horn lantern with the panes of horn left
out. The urchin uses its spines as feet; for it rests its weight on
these, and then moving shifts from place to place.

The urchins

are devoid of flesh, and this is a character
peculiar to them; and while they are in all cases empty and devoid
of any flesh within, they are in all cases furnished with the black
formations. There are several species of the urchin, and one of
these is that which is made use of for food; this is the kind in which
are found the so-called eggs, large and edible, in the larger and
smaller specimens alike; for even when as yet very small they are
provided with them. There are two other species, the spatangus, and
the so-called bryssus, these animals are pelagic and scarce.
Further, there are the echinometrae, or 'mother-urchins', the
largest in size of all the species. In addition to these there is
another species, small in size, but furnished with large hard
spines; it lives in the sea at a depth of several fathoms; and is used
by some people as a specific for cases of strangury. In the
neighbourhood of Torone there are sea-urchins of a white colour,
shells, spines, eggs and all, and that are longer than the ordinary
sea-urchin. The spine in this species is not large nor strong, but
rather limp; and the black formations in connexion with the mouth
are more than usually numerous, and communicate with the external
duct, but not with one another; in point of fact, the animal is in a
manner divided up by them. The edible urchin moves with greatest
freedom and most often; and this is indicated by the fact that these
urchins have always something or other on their spines.

And, by the way,

the animal found in the shell of the neritae is a
separate species, like to the other in most respects; but of its
bifurcate feet or claws, the right-hand one is small and the left-hand
one is large, and it progresses chiefly by the aid of this latter
and larger one. (In the shells of these animals, and in certain
others, there is found a parasite whose mode of attachment is similar.
The particular one which we have just described is named the
cyllarus.)

The nerites has a smooth large round shell, and resembles the
ceryx in shape, only the poppy-juice is, in its case, not black but
red. It clings with great force near the middle. In calm weather,
then, they go free afield, but when the wind blows the carcinia take
shelter against the rocks: the neritae themselves cling fast like
limpets; and the same is the case with the haemorrhoid or aporrhaid
and all others of the like kind. And, by the way, they cling to the
rock, when they turn back their operculum, for this operculum seems
like a lid; in fact this structure represents the one part, in the
stromboids, of that which in the bivalves is a duplicate shell. The
interior of the animal is fleshy, and the mouth is inside. And it is
the same with the haemorrhoid, the purple murex, and all suchlike
animals.

Such of the little crabs as have the left foot or claw the
bigger of the two are found in the neritae, but not in the stromboids.
are some snail-shells which have inside them creatures resembling
those little crayfish that are also found in fresh water. These
creatures, however, differ in having the part inside the shells But as
to the characters, you are referred to my Treatise on Anatomy.

The so-called carcinium or hermit crab is in a way intermediate
between the crustaceans and the testaceans. In its nature it resembles
the crawfish kind, and it is born simple of itself, but by its habit
of introducing itself into a shell and living there it resembles the
testaceans, and so appears to partake of the characters of both kinds.
In shape, to give a simple illustration, it resembles a spider, only
that the part below the head and thorax is larger in this creature
than in the spider. It has two thin red horns, and underneath these
horns two long eyes, not retreating inwards, nor turning sideways like
the eyes of the crab, but protruding straight out; and underneath
these eyes the mouth, and round about the mouth several hair-like
growths, and next after these two bifurcate legs or claws, whereby
it draws in objects towards itself, and two other legs on either side,
and a third small one. All below the thorax is soft, and when opened
in dissection is found to be sallow-coloured within. From the mouth
there runs a single passage right on to the stomach, but the passage
for the excretions is not discernible. The legs and the thorax are
hard, but not so hard as the legs and the thorax of the crab. It
does not adhere to its shell like the purple murex and the ceryx,
but can easily slip out of it. It is longer when found in the shell of
the stromboids than when found in the shell of the neritae.

The non-spiral

univalves and bivalves are in some respect
similar in construction, and in some respects dissimilar, to the
spiral testaceans. They all have a head and horns, and a mouth, and
the organ resembling a tongue; but these organs, in the smaller
species, are indiscernible owing to the minuteness of these animals,
and some are indiscernible even in the larger species when dead, or
when at rest and motionless. They all have the mecon, or poppy, but
not all in the same place, nor of equal size, nor similarly open to
observation; thus, the limpets have this organ deep down in the bottom
of the shell, and the bivalves at the hinge connecting the two valves.
They also have in all cases the hairy growths or beards, in a circular
form, as in the scallops. And, with regard to the so-called 'egg',
in those that have it, when they have it, it is situated in one of the
semi-circles of the periphery, as is the case with the white formation
in the snail; for this white formation in the snail corresponds to the
so-called egg of which we are speaking. But all these organs, as has
been stated, are distinctly traceable in the larger species, while
in the small ones they are in some cases almost, and in others
altogether, indiscernible. Hence they are most plainly visible in
the large scallops; and these are the bivalves that have one valve
flat-shaped, like the lid of a pot. The outlet of the excretion is
in all these animals (save for the exception to be afterwards related)
on one side; for there is a passage whereby the excretion passes
out. (And, remember, the mecon or poppy, as has been stated, is an
excretion in all these animals-an excretion enveloped in a
membrane.) The so-called egg has no outlet in any of these
creatures, but is merely an excrescence in the fleshy mass; and it
is not situated in the same region with the gut, but the 'egg' is
situated on the right-hand side and the gut on the left. Such are
the relations of the anal vent in most of these animals; but in the
case of the wild limpet (called by some the 'sea-ear'), the residuum
issues beneath the shell, for the shell is perforated to give an
outlet. In this particular limpet the stomach is seen coming after the
mouth, and the egg-shaped formations are discernible. But for the
relative positions of these parts you are referred to my Treatise on
Anatomy.

The spiral-shaped

testaceans are all similarly constructed, but
differ from one another, as has been said, in the way of excess or
defect (for the larger species have larger and more conspicuous
organs, and the smaller have smaller and less conspicuous), and,
furthermore, in relative hardness or softness, and in other such
accidents or properties. All the stromboids, for instance, have the
flesh that extrudes from the mouth of the shell, hard and stiff;
some more, and some less. From the middle of this protrudes the head
and two horns, and these horns are large in the large species, but
exceedingly minute in the smaller ones. The head protrudes from them
all in the same way; and, if the animal be alarmed, the head draws
in again. Some of these creatures have a mouth and teeth, as the
snail; teeth sharp, and small, and delicate. They have also a
proboscis just like that of the fly; and the proboscis is
tongue-shaped. The ceryx and the purple murex have this organ firm and
solid; and just as the myops, or horse-fly, and the oestrus, or
gadfly, can pierce the skin of a quadruped, so is that proboscis
proportionately stronger in these testaceans; for they bore right
through the shells of other shell-fish on which they prey. The stomach
follows close upon the mouth, and, by the way, this organ in the snail
resembles a bird's crop. Underneath come two white firm formations,
mastoid or papillary in form; and similar formations are found in
the cuttle-fish also, only that they are of a firmer consistency in
the cuttle-fish. After the stomach comes an oesophagus, simple and
long, extending to the poppy or quasi-liver, which is in the innermost
recess of the shell. All these statements may be verified in the
case of the purple murex and the ceryx by observation within the whorl
of the shell. What comes next to the oesophagus is the gut; in fact,
the gut is continuous with the oesophagus, and runs its whole length
uncomplicated to the outlet of the residuum. The gut has its point
of origin in the region of the coil of the mecon, or so-called
'poppy', and is wider hereabouts (for remember, the mecon is for the
most part a sort of excretion in all testaceans); it then takes a bend
and runs up again towards the fleshy part, and terminates by the
side of the head, where the animal discharges its residuum; and this
holds good in the case of all stromboid testaceans, whether
terrestrial or marine. From the stomach there is drawn in a parallel
direction with the oesophagus, in the larger snails, a long white duct
enveloped in a membrane, resembling in colour the mastoid formations
higher up; and in it are nicks or interruptions, as in the egg-mass of
the crawfish, only, by the way, the duct of which we are treating is
white and the egg-mass of the crawfish is red. This formation has no
outlet nor duct, but is enveloped in a thin membrane with a narrow
cavity in its interior. And from the gut downward extend black and
rough formations, in close connexion, something like the formations in
the tortoise, only not so black. Marine snails, also, have these
formations, and the white ones, only that the formations are smaller
in the smaller species.

With the ostracoderma, or testaceans, such as the land-snails
and the sea-snails, and all the 'oysters' so-called, and also with the
sea-urchin genus, the fleshy part, in such as have flesh, is similarly
situated to the fleshy part in the crustaceans; in other words, it
is inside the animal, and the shell is outside, and there is no hard
substance in the interior. As compared with one another the testaceans
present many diversities both in regard to their shells and to the
flesh within. Some of them have no flesh at all, as the sea-urchin;
others have flesh, but it is inside and wholly hidden, except the
head, as in the land-snails, and the so-called cocalia, and, among
pelagic animals, in the purple murex, the ceryx or trumpet-shell,
the sea-snail, and the spiral-shaped testaceans in general. Of the
rest, some are bivalved and some univalved; and by 'bivalves' I mean
such as are enclosed within two shells, and by 'univalved' such as are
enclosed within a single shell, and in these last the fleshy part is
exposed, as in the case of the limpet. Of the bivalves, some can
open out, like the scallop and the mussel; for all such shells are
grown together on one side and are separate on the other, so as to
open and shut. Other bivalves are closed on both sides alike, like the
solen or razor-fish. Some testaceans there are, that are entirely
enveloped in shell and expose no portion of their flesh outside, as
the tethya or ascidians.

Next after

the oesophagus comes the stomach, two-horned, to the centre of which
is attached a simple and delicate gut; and the gut terminates
outwards, at the operculum, as has been previously stated. (The crab
has the parts in between the lids in the neighbourhood of the teeth
similar to the same parts in the crawfish.) Inside the trunk is a
sallow juice and some few little bodies, long and white, and others
spotted red. The male differs from the female in size and breadth, and
in respect of the ventral flap; for this is larger in the female
than in the male, and stands out further from the trunk, and is more
hairy (as is the case also with the female in the crawfish).

So much, then, for the organs of the malacostraca or crustacea.

The inner organs of sanguineous animals happen to have specific
designations; for these animals have in all cases the inner viscera,
but this is not the case with the bloodless animals, but what they
have in common with red-blooded animals is the stomach, the
oesophagus, and the gut.

With regard to the crab, it has already been stated that it has
claws and feet, and their position has been set forth; furthermore,
for the most part they have the right claw bigger and stronger than
the left. It has also been stated' that in general the eyes of the
crab look sideways. Further, the trunk of the crab's body is single
and undivided, including its head and any other part it may possess.
Some crabs have eyes placed sideways on the upper part, immediately
under the back, and standing a long way apart, and some have their
eyes in the centre and close together, like the crabs of Heracleotis
and the so-called 'grannies'. The mouth lies underneath the eyes,
and inside it there are two teeth, as is the case with the crawfish,
only that in the crab the teeth are not rounded but long; and over the
teeth are two lids, and in betwixt them are structures such as the
crawfish has besides its teeth. The crab takes in water near by the
mouth, using the lids as a check to the inflow, and discharges the
water by two passages above the mouth, closing by means of the lids
the way by which it entered; and the two passage-ways are underneath
the eyes. When it has taken in water it closes its mouth by means of
both lids, and ejects the water in the way above described. Next after
the teeth comes the oesophagus, very short, so short in fact that
the stomach seems to come straightway after the mouth.

(The following are the properties of the egg and of the convolutes
in the carid.)

The male, by the way, differs from the female in regard to its
flesh, in having in connexion with the chest two separate and distinct
white substances, resembling in colour and conformation the
tentacles of the cuttle-fish, and they are convoluted like the 'poppy'
or quasi-liver of the trumpet-shell. These organs have their
starting-point in 'cotyledons' or papillae, which are situated under
the hindmost feet; and hereabouts the flesh is red and blood-coloured,
but is slippery to the touch and in so far unlike flesh. Off from
the convolute organ at the chest branches off another coil about as
thick as ordinary twine; and underneath there are two granular seminal
bodies in juxta-position with the gut. These are the organs of the
male. The female has red-coloured eggs, which are adjacent to the
stomach and to each side of the gut all along to the fleshy parts,
being enveloped in a thin membrane.

Such are the parts, internal and external, of the carid.

We must now proceed to review their several differentiae.

The crawfish then, as has been said, has two teeth, large and
hollow, in which is contained a juice resembling the mytis, and in
between the teeth is a fleshy substance, shaped like a tongue. After
the mouth comes a short oesophagus, and then a membranous stomach
attached to the oesophagus, and at the orifice Of the stomach are
three teeth, two facing one another and a third standing by itself
underneath. Coming off at a bend from the stomach is a gut, simple and
of equal thickness throughout the entire length of the body until it
reaches the anal vent.

These are all common properties of the crawfish, the carid, and
the crab; for the crab, be it remembered, has two teeth.

Again, the crawfish has a duct attached all the way from the chest
to the anal vent; and this duct is connected with the ovary in the
female, and with the seminal ducts in the male. This passage is
attached to the concave surface of the flesh in such a way that the
flesh is in betwixt the duct and the gut; for the gut is related to
the convexity and this duct to the concavity, pretty much as is
observed in quadrupeds. And the duct is identical in both the sexes;
that is to say, the duct in both is thin and white, and charged with a
sallow-coloured moisture, and is attached to the chest.

All crustaceans

take in water close by the mouth. The crab
discharges it, closing up, as it does so, a small portion of the same,
and the crawfish discharges it by way of the gills; and, by the way,
the gill-shaped organs in the crawfish are very numerous.

The following properties are common to all crustaceans: they
have in all cases two teeth, or mandibles (for the front teeth in
the crawfish are two in number), and in all cases there is in the
mouth a small fleshy structure serving for a tongue; and the stomach
is close to the mouth, only that the crawfish has a little
oesophagus in front of the stomach, and there is a straight gut
attached to it. This gut, in the crawfish and its congeners, and in
the carids, extends in a straight line to the tail, and terminates
where the animal discharges the residuum, and where the female
deposits her spawn; in the crab it terminates where the flap is
situated, and in the centre of the flap. (And by the way, in all these
animals the spawn is deposited outside.) Further, the female has the
place for the spawn running along the gut. And, again, all these
animals have, more or less, an organ termed the 'mytis', or
'poppyjuice'.

The lobster is all over grey-coloured, with a mottling of black.
Its under or hinder feet, up to the big feet or claws, are eight in
number; then come the big feet, far larger and flatter at the tips
than the same organs in the crawfish; and these big feet or claws
are exceptional in their structure, for the right claw has the extreme
flat surface long and thin, while the left claw has the
corresponding surface thick and round. Each of the two claws,
divided at the end like a pair of jaws, has both below and above a set
of teeth: only that in the right claw they are all small and
saw-shaped, while in the left claw those at the apex are saw-shaped
and those within are molar-shaped, these latter being, in the under
part of the cleft claw, four teeth close together, and in the upper
part three teeth, not close together. Both right and left claws have
the upper part mobile, and bring it to bear against the lower one, and
both are curved like bandy-legs, being thereby adapted for
apprehension and constriction. Above the two large claws come two
others, covered with hair, a little underneath the mouth; and
underneath these the gill-like formations in the region of the
mouth, hairy and numerous. These organs the animal keeps in
perpetual motion; and the two hairy feet it bends and draws in towards
its mouth. The feet near the mouth are furnished also with delicate
outgrowing appendages. Like the crawfish, the lobster has two teeth,
or mandibles, and above these teeth are its antennae, long, but
shorter and finer by far than those of the crawfish, and then four
other antennae similar in shape, but shorter and finer than the
others. Over these antennae come the eyes, small and short, not
large like the eyes of the crawfish. Over the eyes is a peaky rough
projection like a forehead, larger than the same part in the crawfish;
in fact, the frontal part is more pointed and the thorax is much
broader in the lobster than in the crawfish, and the body in general
is smoother and more full of flesh. Of the eight feet, four are
bifurcate at the extremities, and four are undivided. The region of
the so-called neck is outwardly divided into five divisions, and
sixthly comes the flattened portion at the end, and this portion has
five flaps, or tail-fins; and the inner or under parts, into which the
female drops her spawn, are four in number and hairy, and on each of
the aforesaid parts is a spine turned outwards, short and straight.
The body in general and the region of the thorax in particular are
smooth, not rough as in the crawfish; but on the large claws the outer
portion has larger spines. There is no apparent difference between the
male and female, for they both have one claw, whichever it may be,
larger than the other, and neither male nor female is ever found
with both claws of the same size.

In the crawfish the male differs from the female: in the female
the first foot is bifurcate, in the male it is undivided; the
belly-fins in the female are large and overlapping on the neck,
while in the male they are smaller and do not overlap; and, further,
on the last feet of the male there are spur-like projections, large
and sharp, which projections in the female are small and smooth.
Both male and female have two antennae in front of the eyes, large and
rough, and other antennae underneath, small and smooth. The eyes of
all these creatures are hard and beady, and can move either to the
inner or to the outer side. The eyes of most crabs have a similar
facility of movement, or rather, in the crab this facility is
developed in a higher degree.

The crawfishes

have five feet on either side, including the
claws at the end; and in like manner the crabs have ten feet in all,
including the claws. Of the carids, the hunch-backed, or prawns,
have five feet on either side, which are sharp-pointed-those towards
the head; and five others on either side in the region of the belly,
with their extremities flat; they are devoid of flaps on the under
side such as the crawfish has, but on the back they resemble the
crawfish. (See diagram.)It is very different with the crangon, or
squilla; it has four front legs on either side, then three thin ones
close behind on either side, and the rest of the body is for the most
part devoid of feet. (See diagram.) Of all these animals the feet
bend out obliquely, as is the case with insects; and the claws, where
claws are found, turn inwards. The crawfish has a tail, and five fins
on it; and the round-backed carid has a tail and four fins; the
squilla also has fins at the tail on either side. In the case of both
the hump-backed carid and the squilla the middle art of the tail is
spinous: only that in the squilla the part is flattened and in the
carid it is sharp-pointed. Of all animals of this genus the crab is
the only one devoid of a rump; and, while the body of the carid and
the crawfish is elongated, that of the crab is rotund.

With regard to the Malacostraca or crustaceans, one species is
that of the crawfish, and a second, resembling the first, is that of
the lobster; the lobster differing from the crawfish in having
claws, and in a few other respects as well. Another species is that of
the carid, and another is that of the crab, and there are many kinds
both of carid and of crab.

Of carids there are the so-called cyphae, or 'hunch-backs', the
crangons, or squillae, and the little kind, or shrimps, and the little
kind do not develop into a larger kind.

Of the crab, the varieties are indefinite and incalculable. The
largest of all crabs is one nicknamed Maia, a second variety is the
pagarus and the crab of Heracleotis, and a third variety is the
fresh-water crab; the other varieties are smaller in size and
destitute of special designations. In the neighbourhood of Phoenice
there are found on the beach certain crabs that are nicknamed the
'horsemen', from their running with such speed that it is difficult to
overtake them; these crabs, when opened, are usually found empty,
and this emptiness may be put down to insufficiency of nutriment.
(There is another variety, small like the crab, but resembling in
shape the lobster.) All these animals, as has been stated, have
their hard and shelly part outside, where the skin is in other
animals, and the fleshy part inside; and the belly is more or less
provided with lamellae, or little flaps, and the female here
deposits her spawn.

There are two others found in shells resembling those of the
testaceans. One of them is nicknamed by some persons the nautilus or
the pontilus, or by others the 'polypus' egg'; and the shell of this
creature is something like a separate valve of a deep scallop-shell.
This polypus lives very often near to the shore, and is apt to be
thrown up high and dry on the beach; under these circumstances it is
found with its shell detached, and dies by and by on dry land. These
polypods are small, and are shaped, as regards the form of their
bodies, like the bolbidia. There is another polypus that is placed
within a shell like a snail; it never comes out of the shell, but
lives inside the shell like the snail, and from time to time protrudes
its feelers.

So much for molluscs.

The males of all these animals differ from the females, and the
difference between the sexes is most marked in the sepia; for the back
of the trunk, which is blacker than the belly, is rougher in the
male than in the female, and in the male the back is striped, and
the rump is more sharply pointed.

There are several species of the octopus. One keeps close to the
surface, and is the largest of them all, and near the shore the size
is larger than in deep water; and there are others, small,
variegated in colour, which are not articles of food. There are two
others, one called the heledone, which differs from its congeners in
the length of its legs and in having one row of suckers-all the rest
of the molluscs having two,-the other nicknamed variously the
bolitaina or the 'onion,' and the ozolis or the 'stinkard'.

The females differ from the males. The males have a duct in
under the oesophagus, extending from the mantle-cavity to the lower
portion of the sac, and there is an organ to which it attaches,
resembling a breast; (see diagram) in the female there are two of
these organs, situated higher up; (see diagram) with both sexes there
are underneath these organs certain red formations. The egg of the
octopus is single, uneven on its surface, and of large size; the
fluid substance within is all uniform in colour, smooth, and in
colour white; the size of the egg is so great as to fill a vessel
larger than the creature's head. The sepia has two sacs, and inside
them a number of eggs, like in appearance to white hailstones. For
the disposition of these parts I must refer to my anatomical
diagrams.

In the sepia, the teuthis, and the teuthus the hard parts are
within, towards the back of the body; those parts are called in one
the sepium, and in the other the 'sword'. They differ from one
another, for the sepium in the cuttle-fish and teuthus is hard and
flat, being a substance intermediate between bone and fishbone, with
(in part) a crumbling, spongy texture, but in the teuthis the part
is thin and somewhat gristly. These parts differ from one another in
shape, as do also the bodies of the animals. The octopus has nothing
hard of this kind in its interior, but it has a gristly substance
round the head, which, if the animal grows old, becomes hard.

Molluscs

have no viscera, but they have what is called a
mytis, and on it a vessel containing a thick black juice; in the sepia
or cuttle-fish this vessel is the largest, and this juice is most
abundant. All molluscs, when frightened, discharge such a juice, but
the discharge is most copious in the cuttle-fish. The mytis, then,
is situated under the mouth, and the oesophagus runs through it; and
down below at the point to which the gut extends is the vesicle of the
black juice, and the animal has the vesicle and the gut enveloped in
one and the same membrane, and by the same membrane, same orifice
discharges both the black juice and the residuum. The animals have
also certain hair-like or furry growths in their bodies.

In all cases the head comes after the feet, in the middle of the
feet that are called arms or feelers. There is here situated a
mouth, and two teeth in the mouth; and above these two large eyes, and
betwixt the eyes a small cartilage enclosing a small brain; and within
the mouth it has a minute organ of a fleshy nature, and this it uses
as a tongue, for no other tongue does it possess. Next after this,
on the outside, is what looks like a sac; the flesh of which it is
made is divisible, not in long straight strips, but in annular flakes;
and all molluscs have a cuticle around this flesh. Next after or at
the back of the mouth comes a long and narrow oesophagus, and close
after that a crop or craw, large and spherical, like that of a bird;
then comes the stomach, like the fourth stomach in ruminants; and
the shape of it resembles the spiral convolution in the trumpet-shell;
from the stomach there goes back again, in the direction of the mouth,
thin gut, and the gut is thicker than the oesophagus. (See diagram.)

Stretching out its feet, it swims obliquely in the direction of
the so-called head, and by this mode of swimming it can see in
front, for its eyes are at the top, and in this attitude it has its
mouth at the rear. The 'head', while the creature is alive, is hard,
and looks as though it were inflated. It apprehends and retains
objects by means of the under-surface of its arms, and the membrane in
between its feet is kept at full tension; if the animal get on to
the sand it can no longer retain its hold.

There is a difference between the octopus and the other molluscs
above mentioned: the body of the octopus is small, and his feet are
long, whereas in the others the body is large and the feet short; so
short, in fact, that they cannot walk on them. Compared with one
another, the teuthis, or calamary, is long-shaped, and the sepia
flat-shaped; and of the calamaries the so-called teuthus is much
bigger than the teuthis; for teuthi have been found as much as five
ells long. Some sepiae attain a length of two ells, and the feelers of
the octopus are sometimes as long, or even longer. The species teuthus
is not a numerous one; the teuthus differs from the teuthis in
shape; that is, the sharp extremity of the teuthus is broader than
that of the other, and, further, the encircling fin goes all round the
trunk, whereas it is in part lacking in the teuthis; both animals
are pelagic.

The octopus, by the way, uses his feelers either as feet or hands;
with the two which stand over his mouth he draws in food, and the last
of his feelers he employs in the act of copulation; and this last one,
by the way, is extremely sharp, is exceptional as being of a whitish
colour, and at its extremity is bifurcate; that is to say, it has an
additional something on the rachis, and by rachis is meant the
smooth surface or edge of the arm on the far side from the suckers.
(See diagram.)

In front of the sac and over the feelers they have a hollow
tube, by means of which they discharge any sea-water that they may
have taken into the sac of the body in the act of receiving food by
the mouth. They can shift the tube from side to side, and by means
of it they discharge the black liquid peculiar to the animal.