26 EVENINGS AT THE MICROSCOPE. 



which they float ; and each independently of the rest, 

 BO 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 spiculnm, as it 

 assumes or leaves the reflecting 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 IVom 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 flshes widely diff'ering in size, structure, and 

 habits ; as the Gudgeon and Minnow, the Fike 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 trifling variations in tlie 

 comparative length and breadth. The colouring mat- 

 ter is lodo-ed in lengthened cvlindrical cells, arrano^ed 

 side bv side, and running across the scale: that is, in a 

 direction at right angles to the lateral line. 



