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History of Animals   

castration, and actually to impregnate her.)
So much then for the properties of testicles in male animals.
In female animals furnished with a womb, the womb is not in all
cases the same in form or endowed with the same properties, but both
in the vivipara and the ovipara great diversities present
themselves. In all creatures that have the womb close to the genitals,
the womb is two-horned, and one horn lies to the right-hand side and
the other to the left; its commencement, however, is single, and so is
the orifice, resembling in the case of the most numerous and largest
animals a tube composed of much flesh and gristle. Of these parts
one is termed the hystera or delphys, whence is derived the word
adelphos, and the other part, the tube or orifice, is termed metra. In
all biped or quadruped vivipara the womb is in all cases below the
midriff, as in man, the dog, the pig, the horse, and the ox; the
same is the case also in all horned animals. At the extremity of the
so-called ceratia, or horns, the wombs of most animals have a twist or
In the case of those ovipara that lay eggs externally, the wombs
are not in all cases similarly situated. Thus the wombs of birds are
close to the midriff, and the wombs of fishes down below, just like
the wombs of biped and quadruped vivipara, only that, in the case of
the fish, the wombs are delicately formed, membranous, and
elongated; so much so that in extremely small fish, each of the two
bifurcated parts looks like a single egg, and those fishes whose egg
is described as crumbling would appear to have inside them a pair of
eggs, whereas in reality each of the two sides consists not of one but
of many eggs, and this accounts for their breaking up into so many
The womb of birds has the lower and tubular portion fleshy and
firm, and the part close to the midriff membranous and exceedingly
thin and fine: so thin and fine that the eggs might seem to be outside
the womb altogether. In the larger birds the membrane is more
distinctly visible, and, if inflated through the tube, lifts and
swells out; in the smaller birds all these parts are more indistinct.
The properties of the womb are similar in oviparous quadrupeds, as
the tortoise, the lizard, the frog and the like; for the tube below is
single and fleshy, and the cleft portion with the eggs is at the top
close to the midriff. With animals devoid of feet that are
internally oviparous and viviparous externally, as is the case with
the dogfish and the other so-called Selachians (and by this title we
designate such creatures destitute of feet and furnished with gills as
are viviparous), with these animals the womb is bifurcate, and
beginning down below it extends as far as the midriff, as in the
case of birds. There is also a narrow part between the two horns
running up as far as the midriff, and the eggs are engendered here and
above at the origin of the midriff; afterwards they pass into the
wider space and turn from eggs into young animals. However, the
differences in respect to the wombs of these fishes as compared with
others of their own species or with fishes in general, would be more
satisfactorily studied in their various forms in specimens under
The members of the serpent genus also present divergencies either
when compared with the above-mentioned creatures or with one
another. Serpents as a rule are oviparous, the viper being the only
viviparous member of the genus. The viper is, previously to external
parturition, oviparous internally; and owing to this perculiarity
the properties of the womb in the viper are similar to those of the
womb in the selachians. The womb of the serpent is long, in keeping
with the body, and starting below from a single duct extends
continuously on both sides of the spine, so as to give the
impression of thus being a separate duct on each side of the spine,
until it reaches the midriff, where the eggs are engendered in a
row; and these eggs are laid not one by one, but all strung
together. (And all animals that are viviparous both internally and

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