250 MINUTE MARVELS OF NAFURE 



magnified to reveal its scales. These are covered 

 externally with the fine membrane which contains 

 the pigment cells. These can be seen as dark- 

 coloured spots amongst the scales. The scales 



Fig. 169. The scaly skin of tlie dog-fish 



themselves can be removed, and are composed of 

 a number of rounded or angular bodies impreg- 

 nated with calcareous matter. One of these 

 scales, considerably magnified, is shown in 

 Fig. 172. Those readers who keep gold-fish 



