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feet, also the secreting and excreting lachrymal apparatus, 

 but there is no third eye-lid, although the fold of conjunctiva 

 at the inner canthus, "plica semilunaris," is rudimental of 

 it, and there is no Harderian gland. In quadrupeds the 

 third lid is superadded ; generally contains a cartilage, consis- 

 tent and elastic; connected with this lid is the Harderian 

 gland. 



" I shall confine my observations, on the present occasion, 

 to the condition of these organs in the elephant. This animal, 

 it is well known, is furnished with a highly developed middle 

 eye-lid, or " membrana nictitans," the anatomy of which, 

 however, I do not find has been correctly or fully described 

 by authors. 



" Camper's account of it is (torn. ii. p. 137) : ' The third 

 eye-lid, very thick and fleshy, moves obliquely towards the 

 external angle of the eye, as in Ruminants ; the motion is 

 directed by two muscles, not found in any other quadruped. 

 The first, which serves to draw the membrane over the eye, 

 is attached obliquely to the inferior edge of the orbit, at a 

 considerable distance from the outer angle. The second 

 muscle, which may be regarded as the antagonist to the for- 

 mer, retracts this organ towards the inner angle.' 



*♦. In the Encyclopedie Methodique, by Vicq d'Azyr and 

 H. Cloquet (torn. iii. p. 187): 'The third eye-lid presents 

 two strong muscles: the elevator penetrates deeply into the 

 orbit,- beneath the inferior oblique muscle, to be attached 

 near the optic hole ; the other muscle, destined to retract this 

 membrane, fixes the anterior angle of the corresponding fibro- 

 cartilage to the internal part of the circumference of the 

 orbit.' 



" In Todd's Cyclopedia of Anatomy, (Art. ' Pacchyder- 

 mata,' p. 876, by R. Jones), the author observes : ' The 

 third eye-lid is very largely developed in the elephant, and 

 can be drawn over the eye-ball to a considerable distance to- 

 wards the outer angle of the eye. It is provided with two 



