Of crustaceans,

the female crawfish after copulation conceives and
retains its eggs for about three months, from about the middle of
May to about the middle of August; they then lay the eggs into the
folds underneath the belly, and their eggs grow like grubs. This
same phenomenon is observable in molluscs also, and in such fishes
as are oviparous; for in all these cases the egg continues to grow.

The spawn of the crawfish is of a loose or granular consistency,
and is divided into eight parts; for corresponding to each of the
flaps on the side there is a gristly formation to which the spawn is
attached, and the entire structure resembles a cluster of grapes;
for each gristly formation is split into several parts. This is
obvious enough if you draw the parts asunder; but at first sight the
whole appears to be one and indivisible. And the largest are not those
nearest to the outlet but those in the middle, and the farthest off
are the smallest. The size of the small eggs is that of a small seed
in a fig; and they are not quite close to the outlet, but placed
middleways; for at both ends, tailwards and trunkwards, there are
two intervals devoid of eggs; for it is thus that the flaps also grow.
The side flaps, then, cannot close, but by placing the end flap on
them the animal can close up all, and this end-flap serves them for
a lid. And in the act of laying its eggs it seems to bring them
towards the gristly formations by curving the flap of its tail, and
then, squeezing the eggs towards the said gristly formations and
maintaining a bent posture, it performs the act of laying. The gristly
formations at these seasons increase in size and become receptive of
the eggs; for the animal lays its eggs into these formations, just
as the sepia lays its eggs among twigs and driftwood.

There is a particular

species that is named the 'aplysia' or the
'unwashable', from the circumstance that it cannot be cleaned. This
species has the large open and visible pores, but all the rest of
the body is close-textured; and, if it be dissected, it is found to be
closer and more glutinous than the ordinary sponge, and, in a word,
something lung like in consistency. And, on all hands, it is allowed
that this species is sensitive and long-lived. They are
distinguished in the sea from ordinary sponges from the circumstance
that the ordinary sponges are white while the slime is in them, but
that these sponges are under any circumstances black.

And so much with regard to sponges and to generation in the
testaceans.

Whilst they are still alive and before they are washed and
cleaned, they are blackish in colour. Their attachment is not made
at one particular spot, nor is it made all over their bodies; for
vacant pore-spaces intervene. There is a kind of membrane stretched
over the under parts; and in the under parts the points of
attachment are the more numerous. On the top most of the pores are
closed, but four or five are open and visible; and we are told by some
that it is through these pores that the animal takes its food.

The sponge breeds parasites,

worms, and other creatures, on
which, if they be detached, the rock-fishes prey, as they prey also on
the remaining stumps of the sponge; but, if the sponge be broken
off, it grows again from the remaining stump and the place is soon
as well covered as before.

The largest of all sponges are the loose-textured ones, and
these are peculiarly abundant on the coast of Lycia. The softest are
the close-textured sponges; for, by the way, the so-called sponges
of Achilles are harder than these. As a general rule, sponges that are
found in deep calm waters are the softest; for usually windy and
stormy weather has a tendency to harden them (as it has to harden
all similar growing things), and to arrest their growth. And this
accounts for the fact that the sponges found in the Hellespont are
rough and close-textured; and, as a general rule, sponges found beyond
or inside Cape Malea are, respectively, comparatively soft or
comparatively hard. But, by the way, the habitat of the sponge
should not be too sheltered and warm, for it has a tendency to
decay, like all similar vegetable-like growths. And this accounts
for the fact that the sponge is at its best when found in deep water
close to shore; for owing to the depth of the water they enjoy shelter
alike from stormy winds and from excessive heat.

Sponges

grow spontaneously either attached to a rock or on
sea-beaches, and they get their nutriment in slime: a proof of this
statement is the fact that when they are first secured they are
found to be full of slime. This is characteristic of all living
creatures that get their nutriment by close local attachment. And,
by the way, the close-textured sponges are weaker than the more openly
porous ones because their attachment extends over a smaller area.

It is said that the sponge is sensitive; and as a proof of
this statement they say that if the sponge is made aware of an attempt
being made to pluck it from its place of attachment it draws itself
together, and it becomes a difficult task to detach it. It makes a
similar contractile movement in windy and boisterous weather,
obviously with the object of tightening its hold. Some persons express
doubts as to the truth of this assertion; as, for instance, the people
of Torone.

Moreover

the animals that are unfurnished with shells grow
spontaneously, like the testaceans, as, for instance, the
sea-nettles and the sponges in rocky caves.

Of the sea-nettle, or sea-anemone, there are two species; and of
these one species lives in hollows and never loosens its hold upon the
rocks, and the other lives on smooth flat reefs, free and detached,
and shifts its position from time to time. (Limpets also detach
themselves, and shift from place to place.)

In the chambered cavities of sponges pinna-guards or parasites are
found. And over the chambers there is a kind of spider's web, by the
opening and closing of which they catch mute fishes; that is to say,
they open the web to let the fish get in, and close it again to entrap
them.

Of sponges there are three species; the first is of loose porous
texture, the second is close textured, the third, which is nicknamed
'the sponge of Achilles', is exceptionally fine and close-textured and
strong. This sponge is used as a lining to helmets and greaves, for
the purpose of deadening the sound of the blow; and this is a very
scarce species. Of the close textured sponges such as are particularly
hard and rough are nicknamed 'goats'.

Shell-fish

(, then, grow in the way above mentioned; and some
of them grow in shallow water, some on the sea-shore, some in rocky
places, some on hard and stony ground, and some in sandy places.) Some
shift about from place to place, others remain permanent on one
spot. Of those that keep to one spot the pinnae are rooted to the
ground; the razor-fish and the clam keep to the same locality, but are
not so rooted; but still, if forcibly removed they die.

(The star-fish is naturally so warm that whatever it lays hold
of is found, when suddenly taken away from the animal, to have
undergone a process like boiling. Fishermen say that the star-fish
is a great pest in the Strait of Pyrrha. In shape it resembles a
star as seen in an ordinary drawing. The so-called 'lungs' are
generated spontaneously. The shells that painters use are a good
deal thicker, and the bloom is outside the shell on the surface. These
creatures are mostly found on the coast of Caria.)

The hermit-crab grows spontaneously out of soil and slime, and
finds its way into untenanted shells. As it grows it shifts to a
larger shell, as for instance into the shell of the nerites, or of the
strombus or the like, and very often into the shell of the small
ceryx. After entering new shell, it carries it about, and begins again
to feed, and, by and by, as it grows, it shifts again into another
larger one.

As a general rule,

then, all testaceans grow by spontaneous
generation in mud, differing from one another according to the
differences of the material; oysters growing in slime, and cockles and
the other testaceans above mentioned on sandy bottoms; and in the
hollows of the rocks the ascidian and the barnacle, and common
sorts, such as the limpet and the nerites. All these animals grow with
great rapidity, especially the murex and the scallop; for the murex
and the scallop attain their full growth in a year. In some of the
testaceans white crabs are found, very diminutive in size; they are
most numerous in the trough shaped mussel. In the pinna also is
found the so-called pinna-guard. They are found also in the scallop
and in the oyster; these parasites never appear to grow in size.
Fishermen declare that the parasite is congenital with the larger
animal. (Scallops burrow for a time in the sand, like the murex.)

The mussel also constructs a honeycomb.

With regard to the limnostreae, or lagoon oysters, wherever you
have slimy mud there you are sure to find them beginning to grow.
Cockles and clams and razor-fishes and scallops row spontaneously in
sandy places. The pinna grows straight up from its tuft of anchoring
fibres in sandy and slimy places; these creatures have inside them a
parasite nicknamed the pinna-guard, in some cases a small carid and in
other cases a little crab; if the pinna be deprived of this
pinna-guard it soon dies.

The same phenomena

are manifested by the ceryx or trumpet-shell;
and the seasons are the same in which the phenomena are observable.
Both animals, also, the murex and the ceryx, have their opercula
similarly situated-and, in fact, all the stromboids, and this is
congenital with them all; and they feed by protruding the so-called
tongue underneath the operculum. The tongue of the murex is bigger
than one's finger, and by means of it, it feeds, and perforates
conchylia and the shells of its own kind. Both the murex and the ceryx
are long lived. The murex lives for about six years; and the yearly
increase is indicated by a distinct interval in the spiral convolution
of the shell.

And the qualities, by the way, of this organ are
astringent. It is after the murex has constructed the honeycomb that
the bloom is at its worst. Small specimens they break in pieces,
shells and all, for it is no easy matter to extract the organ; but
in dealing with the larger ones they first strip off the shell and
then abstract the bloom. For this purpose the neck and mecon are
separated, for the bloom lies in between them, above the so-called
stomach; hence the necessity of separating them in abstracting the
bloom. Fishermen are anxious always to break the animal in pieces
while it is yet alive, for, if it die before the process is completed,
it vomits out the bloom; and for this reason the fishermen keep the
animals in creels, until they have collected a sufficient number and
can attend to them at their leisure. Fishermen in past times used
not to lower creels or attach them to the bait, so that very often the
animal got dropped off in the pulling up; at present, however, they
always attach a basket, so that if the animal fall off it is not lost.
The animal is more inclined to slip off the bait if it be full inside;
if it be empty it is difficult to shake it off. Such are the phenomena
connected with the porphyra or murex.

There are many species of the purple murex; and some are
large, as those found off Sigeum and Lectum; others are small, as
those found in the Euripus, and on the coast of Caria. And those
that are found in bays are large and rough; in most of them the
peculiar bloom from which their name is derived is dark to
blackness, in others it is reddish and small in size; some of the
large ones weigh upwards of a mina apiece. But the specimens that
are found along the coast and on the rocks are small-sized, and the
bloom in their case is of a reddish hue. Further, as a general rule,
in northern waters the bloom is blackish, and in southern waters of
a reddish hue. The murex is caught in the spring-time when engaged
in the construction of the honeycomb; but it is not caught at any time
about the rising of the dog-star, for at that period it does not feed,
but conceals itself and burrows. The bloom of the animal is situated
between the mecon (or quasi-liver) and the neck, and the co-attachment
of these is an intimate one. In colour it looks like a white membrane,
and this is what people extract; and if it be removed and squeezed
it stains your hand with the colour of the bloom. There is a kind of
vein that runs through it, and this quasi-vein would appear to be in
itself the bloom.

So much for the copulations of such animals as copulate.

We now proceed to treat of generation both with respect to
copulating and non-copulating animals, and we shall commence with
discussing the subject of generation in the case of the testaceans.

The testacean is almost the only genus that throughout all its
species is non-copulative.

The porphyrae, or purple murices, gather together to some one
place in the spring-time, and deposit the so-called 'honeycomb'.
This substance resembles the comb, only that it is not so neat and
delicate; and looks as though a number of husks of white chick-peas
were all stuck together. But none of these structures has any open
passage, and the porphyra does not grow out of them, but these and all
other testaceans grow out of mud and decaying matter. The substance,
is, in fact, an excretion of the porphyra and the ceryx; for it is
deposited by the ceryx as well. Such, then, of the testaceans as
deposit the honeycomb are generated spontaneously like all other
testaceans, but they certainly come in greater abundance in places
where their congeners have been living previously. At the commencement
of the process of depositing the honeycomb, they throw off a
slippery mucus, and of this the husklike formations are composed.
These formations, then, all melt and deposit their contents on the
ground, and at this spot there are found on the ground a number of
minute porphyrae, and porphyrae are caught at times with these
animalculae upon them, some of which are too small to be
differentiated in form. If the porphyrae are caught before producing
this honey-comb, they sometimes go through the process in
fishing-creels, not here and there in the baskets, but gathering to
some one spot all together, just as they do in the sea; and owing to
the narrowness of their new quarters they cluster together like a
bunch of grapes.

The female elephant

becomes sexually receptive when ten years
old at the youngest, and when fifteen at the oldest; and the male is
sexually capable when five years old, or six. The season for
intercourse is spring. The male allows an interval of three years to
elapse after commerce with a female: and, after it has once
impregnated a female, it has no intercourse with her again. The period
of gestation with the female is two years; and only one young animal
is produced at a time, in other words it is uniparous. And the
embryo is the size of a calf two or three months old.

The female

of the camel is opisthuretic, and submits to the male
in the way above described; and the season for copulation in Arabia is
about the month of October. Its period of gestation is twelve
months; and it is never delivered of more than one foal at a time. The
female becomes sexually receptive and the male sexually capable at the
age of three years. After parturition, an interval of a year elapses
before the female is again receptive to the male.

Bitches

do not submit to the male throughout their lives, but
only until they reach a certain maturity of years. As a general
rule, they are sexually receptive and conceptive until they are twelve
years old; although, by the way, cases have been known where dogs
and bitches have been respectively procreative and conceptive to the
ages of eighteen and even of twenty years. But, as a rule, age
diminishes the capability of generation and of conception with these
animals as with all others.

With regard to the age of the

parents, the litter is the best when they are in their prime; but with
regard to the seasons of the year, the litter is the best that comes
at the beginning of winter; and the summer litter the poorest,
consisting as it usually does of animals small and thin and flaccid.
The boar, if it be well fed, is sexually capable at all hours, night
and day; but otherwise is peculiarly salacious early in the morning.
As it grows old the sexual passion dies away, as we have already
remarked. Very often a boar, when more or less impotent from age or
debility, finding itself unable to accomplish the sexual commerce with
due speed, and growing fatigued with the standing posture, will roll
the sow over on the ground, and the pair will conclude the operation
side by side of one another. The sow is sure of conception if it drops
its lugs in rutting time; if the ears do not thus drop, it may have to
rut a second time before impregnation takes place.

Rams single

out the oldest ewes for copulation, and show no
regard for the young ones. And, as has been stated, the issue of the
younger ewes is poorer than that of the older ones.

The boar is good for breeding purposes until he is three years
of age; but after that age his issue deteriorates, for after that
age his vigour is on the decline. The boar is most capable after a
good feed, and with the first sow it mounts; if poorly fed or put to
many females, the copulation is abbreviated, and the litter is
comparatively poor. The first litter of the sow is the fewest in
number; at the second litter she is at her prime. The animal, as it
grows old, continues to breed, but the sexual desire abates. When they
reach fifteen years, they become unproductive, and are getting old. If
a sow be highly fed, it is all the more eager for sexual commerce,
whether old or young; but, if it be over-fattened in pregnancy, it
gives the less milk after parturition.

In the human species, the male is generative, at the longest, up
to seventy years, and the female up to fifty; but such extended
periods are rare. As a rule, the male is generative up to the age of
sixty-five, and to the age of forty-five the female is capable of
conception.

The ewe bears up to eight years, and, if she be carefully
tended, up to eleven years; in fact, the ram and the ewe are
sexually capable pretty well all their lives long. He-goats, if they
be fat, are more or less unserviceable for breeding; and this, by
the way, is the reason why country folk say of a vine when it stops
bearing that it is 'running the goat'. However, if an over-fat he-goat
be thinned down, he becomes sexually capable and generative.

As a general

rule these animals are sexually
capable when three years old, and they grow better for breeding
purposes until they reach twenty years. The stallion is sexually
capable up to the age of thirty-three years, and the mare up to forty,
so that, in point of fact, the animals are sexually capable all
their lives long; for the stallion, as a rule, lives for about
thirty-five years, and the mare for a little over forty; although,
by the way, a horse has known to live to the age of seventy-five.
The ass and the she-ass are sexually capable when thirty months old;
but, as a rule, they are not generatively mature until they are
three years old, or three years and a half. An instance has been known
of a she-ass bearing and bringing forth a foal when only a year old. A
cow has been known to calve when only a year old, and the calf grew as
big as might be expected, but no more. So much for the dates in time
at which these animals attain to generative capacity.

The following are the ages at which various animals become
capacitated for sexual commerce. The ewe and the she-goat are sexually
mature when one year old, and this statement is made more
confidently in respect to the she-goat than to the ewe; the ram and
the he-goat are sexually mature at the same age. The progeny of very
young individuals among these animals differs from that of other
males: for the males improve in the course of the second year, when
they become fully mature. The boar and the sow are capable of
intercourse when eight months old, and the female brings forth when
one year old, the difference corresponding to her period of gestation.
The boar is capable of generation when eight months old, but, with a
sire under a year in age, the litter is apt to be a poor one. The
ages, however, are not invariable; now and then the boar and the sow
are capable of intercourse when four months old, and are capable of
producing a litter which can be reared when six months old; but at
times the boar begins to be capable of intercourse when ten months. He
continues sexually mature until he is three years old. The dog and the
bitch are, as a rule, sexually capable and sexually receptive when a
year old, and sometimes when eight months old; but the priority in
date is more common with the dog than with the bitch. The period of
gestation with the bitch is sixty days, or sixty-one, or sixty-two, or
sixty-three at the utmost; the period is never under sixty days, or,
if it is, the litter comes to no good. The bitch, after delivering a
litter, submits to the male in six months, but not before. The horse
and the mare are, at the earliest, sexually capable and sexually
mature when two years old; the issue, however, of parents of this
age is small and poor.