. Anatomy of the cat. Cats; Mammals. 4IO SENSE-ORGylNS AND INTEGUMENT. broad yellowish lines. They secrete a substance which pre- vents the adhesion of the edges of the two lids. On the edge of each eyelid, three to four millimeters from the medial angle of the eye, is one of the openings of the lachrymal canals. At the medial angle of the eye is the large nictitating membrane (membrana nictitans), or "third eyelid," corre- sponding to the plica semilunaris of man. In the cat this is large and may cover the whole surface of the eye. It is supported (Fig. 165) by a broad central strip
. Anatomy of the cat. Cats; Mammals. 4IO SENSE-ORGylNS AND INTEGUMENT. broad yellowish lines. They secrete a substance which pre- vents the adhesion of the edges of the two lids. On the edge of each eyelid, three to four millimeters from the medial angle of the eye, is one of the openings of the lachrymal canals. At the medial angle of the eye is the large nictitating membrane (membrana nictitans), or "third eyelid," corre- sponding to the plica semilunaris of man. In the cat this is large and may cover the whole surface of the eye. It is supported (Fig. 165) by a broad central strip of carti- ^ , , lae^e (a), passing from its edge to its inner Fig. 165. — Inner t> v -" r & t> Surface of Mem- angle, and the inner end of this cartilage is BRANA NICTITANS, g^rroundcd, on the medial (concave) side of showing the support- 111 1 tt mg cartilage and liar- the membrane, by the large lobulated Har- derian glands a, sup- ^^^^^^ gla„ds (b). porting cartilage; o, ^ ^ ' ^ iiarderian glands; c. The conjunctiva is the thin membrane outer edge. covering the inner surface of the lids, the outer surface of the eyeball, and both surfaces of the nictitating membrane. The muscles of the eyelids are M. orbicularis oculi, already described (page 98), and M. levator palpebrae superioris, described below, 3. Lachrymal Apparatus.—The lachrymal gland is a large reddish gland, not lobulated externally, which lies on the surface of the eyeball just beneath the lateral angle of the eye. The gland is situated immediately craniad of, and in contact with, the zygomatic process of the frontal bone (Fig. 154, 11, page 374). It is flat and about one centimeter in diameter. The ducts which pass from the gland to the eye are not visible to the naked eye. The fluid secreted by the gland collects at the medial angle of the eye and passes into the two openings of the lachrymal canals, one of which is found on the pigmented edge of each lid, three or four milli- meters from t
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Keywords: ., bookcentury1900, bookcollect, booksubjectcats, booksubjectmammals
