26 EVENINGS AT THE MICEOSCOPE. 



■which they float; and each independently of the rest, 

 so as to convey the impression to the observer that each 

 is animated with life, though the scale be taken from a 

 fish some days dead. Owing to this irregular motion, 

 and consequent change of position, each spiculum, as it 

 assumes or leaves the i-eflecting angle, is momentarily 

 brightening or waning, flashing out or retiring into 

 darkness, producing a magic effect on the admiring ob- 

 server. To this property, I suppose, is to be attributed 

 the beautiful pearly play of light that marks these lovely 

 fishes, as distinguished from the light reflected by an 

 uniformly polished surface. I have found the pearly 

 pigment of the scales to be provided with similar spic- 

 ula in fishes widely differing in size, structui'e, and 

 habits ; as the Grudgeon and Minnow, the Pike and the 

 Marine Bream. The spicula of these fishes agree in 

 general form with those of the Gold-fish ; and also in 

 size, with the exception of trifiing variations in the 

 comparative length and breadth. The colouring mat- 

 ter is lodged in lengthened cylindrical cells, arranged 

 side by side, and running across the scale ; that is, in a 

 direction at I'ight angles to the lateral line. 



