THE EYE. 399 



space called Glabella, the existence of which adds much to the 

 calm and intellectual expression of the human countenance; 

 whereas, the junction of the two eyebrows, by the hairs filling 

 up this space, gives a gloomy, and, occasionally, a ferocious 

 appearance. 



The margins of the eyelids are also furnished with hairs, 

 {Cilia,) the roots of which are insinuated between the skin and 

 the tarsi cartilages: the most deeply seated seem, indeed, to pe- 

 netrate the latter. The hairs of the upper lid are longer and 

 more numerous than those of the lower: they are concave up- 

 wards, while the latter are concave downwards, so that the con- 

 vexities of the two ranges of hairs come in contact when the 

 eyelids are closed. The hairs of each cilium are disposed into 

 three or four rows, by which a long brush is formed, the central 

 hairs of which are longer and larger than any others. 



The hairs of the supercilia and of the cilia resemble one ano- 

 ther strongly, for, when examined closely, each one will be 

 found to have a bulbous soft root, just beyond which there is a 

 narrow part. The middle of the hair is swollen, and its ex- 

 ternal extremity is brought to a fine point. These hairs cor- 

 respond in colour with the hairs of the head. 



When the orbicularis muscle is removed, a ligamentous or 

 fibrous membrane is found passing from the external margin of 

 the orbit to the corresponding margin of the palpebral cartilages, 

 and separating the eyelids from the parts contained within the 

 orbit. There is a partial decussation of the fibres of this mem- 

 brane, from the external commissure of the cartilages to the ex- 

 ternal edge of the orbit; it has more firmness than any other 

 part of the membrane, and is the external palpebral ligament,-' 

 (Ligamentum Palpebrale Exlernum.} On the side of the internal 

 canthus of the orbit there is no corresponding ligamentous ex- 

 pansion, but a few irregular fibres, which allow the masses of 

 fat beneath to project forwards between their fasciculi. 



The Palpebral Cartilages (Tarsi) are two in number, one at 

 the margin of each eyelid, to which they communicate a smooth, 

 even surface, from the internal to the external commissure. 

 They are between the orbicularis muscle and the tunica conjunc- 

 tiva. The upper one is larger than the lower, resembles an oval 



