The two
largest ones, then, run side by side and do not meet; the medium-sized
ones meet-and this is particularly visible in fishes,-for they lie
nearer than the large ones to the brain; the smallest pair are the
most widely separate from one another, and do not meet.
Inside the neck is what is termed the oesophagus (whose other
name is derived oesophagus from its length and narrowness), and the
windpipe. The windpipe is situated in front of the oesophagus in all
animals that have a windpipe, and all animals have one that are
furnished with lungs. The windpipe is made up of gristle, is sparingly
supplied with blood, and is streaked all round with numerous minute
veins; it is situated, in its upper part, near the mouth, below the
aperture formed by the nostrils into the mouth-an aperture through
which, when men, in drinking, inhale any of the liquid, this liquid
finds its way out through the nostrils. In betwixt the two openings
comes the so-called epiglottis, an organ capable of being drawn over
and covering the orifice of the windpipe communicating with the mouth;
the end of the tongue is attached to the epiglottis. In the other
direction the windpipe extends to the interval between the lungs,
and hereupon bifurcates into each of the two divisions of the lung;
for the lung in all animals possessed of the organ has a tendency to
be double.
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