114 



THE MICROSCOPE. 



Aug. 



But the scales are there, and if the under side of the 

 skin be examined after it has been taken from the fish, 

 the scales may be readily seen and removed with a pair 

 of tweezers ; fig. 13 represents one of these scales. A 

 piece of the skin of. the eel dried and mounted in Canada 

 balsam shows the scales imbedded in the skin, their ar- 

 rangement and the pigment cells (fig. 14). These, and 



indeed the"scales of nearly all of our fishes, make beau- 

 tiful objects for the polariscope. The different scales 

 vary much in color and tone. It is also interesting to 

 view them as opaque objects. 



By means of the scales, fishes are divided into four or- 

 ders, Cycloid, Ctenoid, Placoid, and Granoid, but most of 

 our common fishes belong to the first two orders. 



