OKGATCS OF SENSE. 



Ill 



its normal elements. "We must give up the idea 

 therefore that these dense laminae consist of fibro- 

 cartilage, for they have only its appearance, without 

 possessing its structure. On their deep surfaces there 

 are from twenty to thirty parallel grooves, which 

 accommodate the Meibomian glands (PL XXVII. 



%. in.). 



The mucous membrane, or conjunctiva, consists of 

 quite a dense layer of connecting tissue, the ocular 

 surface of which is studded with numerous papillae 

 analogous to those of the skin ; its epithelium, which 

 is stratified, resembles that of the skin and mucous 

 membrane of the mouth (Pi. XXVIII. fig. II. 5). 

 This membrane, as is well known, is reflected from 

 the eyelids upon the globe of the eye, to which it 

 becomes intimately attached ; tracing it here to the 

 circumference of the cornea, it is to be remarked that 

 its deep layer becomes gradually thinner, and ceases 

 suddenly by becoming inserted into the amorphous 

 border which surrounds the anterior margin of the 

 cornea (PL XXVIII. fig. II. 4), whilst its epithelial 

 layer continues its course and covers the whole ante- 

 rior surface of the cornea (fig. I. 7 ; fig. II. 5). The 

 vessels and nerves of the cornea present no peculia- 

 rities worthy of note. 



Globe of the Eye. The first proper coat of the eye- 

 ball is formed posteriorly by the scierotica, and in 

 front, by the cornea. The scierotica is an exceeding- 

 ly dense membrane, thicker anteriorly and posteriorly 

 than around the centre of the eye-ball, and consisting 

 of a close tissue of connective and elastic fibres. An- 

 teriorly this membrane adheres very intimately to 



