398 THE EYELIDS. 



rows, the middle of which are the longest. The internal extre- 

 mities of the eyebrows, called the head, occasionally meet ; but 

 most usually, there is an interval between them called glabella, 

 which presents the smoothness and polish of other parts of the 

 forehead, and adds to the open and noble expression of the 

 face. The outer extremity or tail is terminated by a thin 

 series of hairs, (cauda supercilii) near the outer angle of the 

 frontal bone. The color corresponds generally with that of 

 the hair. — 



The Eyelids or Palpehra, 



Are formed by a slit or orifice in the skin (Jlssura palpebra- 

 rum) ; immediately under the skin, surrounding this orifice, is 

 a portion of the orbicularis muscle ; under this portion of the 

 muscle, there is a plate of cartilage, and under the cartilage, a 

 portion of tunica conjunctiva, or membrane that covers the 

 front part of the ball of the eye and lines the eyelids. 



— The eyelids, may be considered two movable fleshy cur- 

 tains, nicely adjusted to one another at their free edges, and to 

 the anterior surface of the ball of the eye which they exactly 

 cover. 



— They are composed of the skin externally, which is so thin 

 as to allow the light partially to pass through it, and which is 

 folded inwards at the free margin of the lids, so as to line their 

 inner surface, where it takes the character of mucous mem- 

 brane, (^tunica conjunctiva) ; from the lids, it it reflected again 

 over the anterior surface of the eyeball, so that the conjunctival 

 linings of both eyelids form one continuous membrane. The 

 lids are two in number, upper and lower, palpebra superioris, 

 palpebra inferioris. They are divided unequally by the trans- 

 verse fissures ; so that the upper lid is considerably the larger. 

 Was it not for this, as the motions of the lower lid are very 

 limited, the eye would be only half uncovered, in what is 

 called, opening the eye. 



— The fissure which separates the lids is not exactly trans- 

 verse ; it is slightly depressed externally. The reverse is said 

 to be the case in regard to the Chinese, in whom the peculiar 



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