THE eel's spectacles AND SCALES. 85 



There is another point in his structure well worthy of 

 observation — it is the spectacles of the eel. The eel 

 has to live amongst mud, stone, &c., and if his eyes 

 were not protected, it is reasonable to suppose that its 

 delicate structure would occasionally get wounded. 



Over the eye, therefore, we find a wonderful eyeglass. 

 This is formed by the ordinary scale-covered skin of 

 the head, just at the point where it passes over the eye, 

 taking the form of a thin but strong transparent mem- 

 brane, which affords an admirable guard against any 

 injury occurring to the organs of sight. The eye itself 

 is a very beautiful round ball, the iris black pencilled 

 with tints of a golden hue. If the eyeball be cut in 

 two the lens will immediately pop out, the most lovely 

 little crystal ball, in brilliancy equal, if not superior to, 

 a diamond. The reader should dissect off for himself 

 these curious spectacles of the eel ; by di-ying the skin 

 of the head on a piece of window-glass their structure 

 will at once be seen. 



The common snake has a somewhat similar provision, 

 only, whereas he lives on dry land, his spectacles have 

 a firmer and horny consistency. Tlie structure of the 

 snakes' eye-glasses may be easily seen in the shed skin 

 of the snake (and snakes shedding their skin frequently 

 during the year). When the snake sheds his skin it is 

 found turned inside out. Thus the transparent eye- 

 protectors easily become discernible. 



A question has often arisen as to whether eels have or 

 have not scales. Again look for yourself. Place a por- 

 tion of an eelskin on a microscope slide or window-glass 

 and as it dries you will see quite plainly the scales come 

 into view as the slimy membrane in which they are 

 imbedded gradually dries uj). These scales are of an 

 oval shape, somewhat resembling carraway seeds. 



