el,
the upper part of which has been bent into a triangular shape. Its front
corner (pl. V, 1) may be both seen and felt in the throat, and the
general position of the voicebox is thereby at once indicated. The
framework of the voicebox consists of five parts. 1st. The Ring
cartilage (pl. V, 2) is so named on account of its general resemblance
to a signet ring. It is narrow in front, and has the part corresponding
to the seal behind; the upper border (pl. V, 8, 4) rises very
considerably towards the back, where it is about an inch high. 2nd.
Riding upon this, as it were, with its hollow part towards the back,
is the Shield cartilage (pl. V, 5), which consists of two plates united
in front at an angle which forms the prominence referred to just now as
that corner of the triangular funnel (pl. V, 1) which may be both seen
and felt in the throat, and which is commonly called the Adam's Apple.
It protects the interior and more delicate parts of the voice apparatus,
from which circumstance it derives its name of shield cartilage. The
plates of the shield have each at the back two horns, the upper and the
lower. With the upper horns (pl. VI, 1, 2) the shield cartilage is
attached by means of bands (pl. VI, 6, 7) to the corresponding
projections (pl. VI, 4, 5) of the tongue-bone (pl. VI, 3), which has the
shape of a horseshoe. With the lower horns (pl. V, 8), of which on our
diagram we can only see one, it moves upon the ring cartilage as upon a
hinge (pl. V, 9).

[Illustration: PLATE V.

SIDE VIEW OF THE VOICEBOX, OR LARYNX.

1. FRONT CORNER OF THE VOICEBOX (LARYNX).

2. RING (CRICOID) CARTILAGE.

3, 4. UPPER BORDER OF THE RING.

5. SHIELD (THYROID) CARTILAGE.

6, 7. UPPER HORNS OF THE SHIELD.

8. RIGHT LOWER HORN OF THE SHIELD.

9. POINT WHERE THE SHIELD MOVES UPON THE RING.

10. RING-SHIELD (CRICO-THYROID) APERTURE COVERED BY MEMBRANE.

11. LID (EPIGLOTTIS).

12. WINDPIPE (TRACHEA).

]

[Illustration: PLATE VI.

FRONT VIEW OF THE VOICEBOX, OR LARYNX.

1, 2. UPPER HORNS OF THE SHIELD.

3. TONGUE (HYOID) BONE.

4, 5. HORNS OF THE TONGUE-BONE.

6, 7. BANDS UNITING THE SHIELD WITH THE TONGUE-BONE.

8, 9. LID.

10, 11. PLATES OF THE SHIELD.

12. RING.

13. ELASTIC BAND UNITING THE SHIELD WITH THE RING.

14. WINDPIPE.

]

This is a very particular point, and I beg the reader particularly to
notice that if the shield cartilage (pl. V, 5) were gradu