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History of Animals   


Again, all viviparous quadrupeds are furnished with kidneys and
a bladder. Of the ovipara that are not quadrupedal there is no
instance known of an animal, whether fish or bird, provided with these
organs. Of the ovipara that are quadrupedal, the turtle alone is
provided with these organs of a magnitude to correspond with the other
organs of the animal. In the turtle the kidney resembles the same
organ in the ox; that is to say, it looks one single organ composed of
a number of small ones. (The bison also resembles the ox in all its
internal parts).

With all animals that are furnished with these parts, the parts
are similarly situated, and with the exception of man, the heart is in
the middle; in man, however, as has been observed, the heart is placed
a little to the left-hand side. In all animals the pointed end of
the heart turns frontwards; only in fish it would at first sight
seem otherwise, for the pointed end is turned not towards the
breast, but towards the head and the mouth. And (in fish) the apex
is attached to a tube just where the right and left gills meet
together. There are other ducts extending from the heart to each of
the gills, greater in the greater fish, lesser in the lesser; but in
the large fishes the duct at the pointed end of the heart is a tube,
white-coloured and exceedingly thick. Fishes in some few cases have an
oesophagus, as the conger and the eel; and in these the organ is
In fishes that are furnished with an undivided liver, the organ
lies entirely on the right side; where the liver is cloven from the
root, the larger half of the organ is on the right side: for in some
fishes the two parts are detached from one another, without any
coalescence at the root, as is the case with the dogfish. And there is
also a species of hare in what is named the Fig district, near Lake
Bolbe, and elsewhere, which animal might be taken to have two livers
owing to the length of the connecting ducts, similar to the
structure in the lung of birds.
The spleen in all cases, when normally placed, is on the
left-hand side, and the kidneys also lie in the same position in all
creatures that possess them. There have been known instances of
quadrupeds under dissection, where the spleen was on the right hand
and the liver on the left; but all such cases are regarded as
In all animals the wind-pipe extends to the lung, and the
manner how, we shall discuss hereafter; and the oesophagus, in all
that have the organ, extends through the midriff into the stomach.
For, by the way, as has been observed, most fishes have no oesophagus,
but the stomach is united directly with the mouth, so that in some
cases when big fish are pursuing little ones, the stomach tumbles
forward into the mouth.
All the afore-mentioned animals have a stomach, and one
similarly situated, that is to say, situated directly under the
midriff; and they have a gut connected therewith and closing at the
outlet of the residuum and at what is termed the 'rectum'. However,
animals present diversities in the structure of their stomachs. In the
first place, of the viviparous quadrupeds, such of the horned
animals as are not equally furnished with teeth in both jaws are
furnished with four such chambers. These animals, by the way, are
those that are said to chew the cud. In these animals the oesophagus
extends from the mouth downwards along the lung, from the midriff to
the big stomach (or paunch); and this stomach is rough inside and
semi-partitioned. And connected with it near to the entry of the
oesophagus is what from its appearance is termed the 'reticulum' (or
honeycomb bag); for outside it is like the stomach, but inside it
resembles a netted cap; and the reticulum is a great deal smaller than

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