DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.6271#0265
( '239 )
-fords and quadrupeds it is very large, forming the rnembraua
nictitans.
7. The tunica conjunctiva, or adnata, a transparent
vascular membrane, reflected from the edge of one eyelid
over the internal part of the eyelid across the bulb, to which
it adheres very finniy, and then over the internal part of the
other eyelid to its edge. It is more loosely connected with
the eyelids than the eye ; and where it passes the c ruea
transparens, it adheres so firmly that it cannot be separated.
Its use is to lubricate the eye by the moisture secreted from
its transparent arteries.
The internal parts of the eye are termed the bulb; they
Constitute the eye, properly so called, and are—
1. The sclerotic membrane. A very firm, hard, white,
horny tunic, into which the muscles of the eye are inserted.
The anterior part of this coat is glassy and transparent, and
projects somewhat; itis railed cornea transparens, to distin-
guish it from the other part, which is also termed cornea opaca.
The optic nerve is inserted into the posterior part of the scle-
rotic membrane, which appears to be an expansion of its
external tunic, continued from the dura mater.
2. Immediately under the sclerotic membrane is a very
vascular, soft, and rough membrane, called the membrana
or tunica choroidea. It adheres to the sclerotic from the
optic nerve, all around to the edge of the transparent cornea
by vessels; but when it arrives here, instead of being con-
tinued around the concavity of the cornea transparens, it
passes straight downwards and inwards, forming the coloured
part of the eye, which is sometimes Mack, blue, &c. This
black or blue part is called the iris, which possesses a con-
tractile power, by some supposed to arise from muscular
fibres, so as- to enlarge or contract the opening in its middle
-fords and quadrupeds it is very large, forming the rnembraua
nictitans.
7. The tunica conjunctiva, or adnata, a transparent
vascular membrane, reflected from the edge of one eyelid
over the internal part of the eyelid across the bulb, to which
it adheres very finniy, and then over the internal part of the
other eyelid to its edge. It is more loosely connected with
the eyelids than the eye ; and where it passes the c ruea
transparens, it adheres so firmly that it cannot be separated.
Its use is to lubricate the eye by the moisture secreted from
its transparent arteries.
The internal parts of the eye are termed the bulb; they
Constitute the eye, properly so called, and are—
1. The sclerotic membrane. A very firm, hard, white,
horny tunic, into which the muscles of the eye are inserted.
The anterior part of this coat is glassy and transparent, and
projects somewhat; itis railed cornea transparens, to distin-
guish it from the other part, which is also termed cornea opaca.
The optic nerve is inserted into the posterior part of the scle-
rotic membrane, which appears to be an expansion of its
external tunic, continued from the dura mater.
2. Immediately under the sclerotic membrane is a very
vascular, soft, and rough membrane, called the membrana
or tunica choroidea. It adheres to the sclerotic from the
optic nerve, all around to the edge of the transparent cornea
by vessels; but when it arrives here, instead of being con-
tinued around the concavity of the cornea transparens, it
passes straight downwards and inwards, forming the coloured
part of the eye, which is sometimes Mack, blue, &c. This
black or blue part is called the iris, which possesses a con-
tractile power, by some supposed to arise from muscular
fibres, so as- to enlarge or contract the opening in its middle