ITATKS, FEATHERS, A^"D SCALES. 



21 



in liavino: the front ed^-es, by whicli thev are dnrino' life 

 imbedded in tlic skin, cnt into waves or sinuosities. 

 Tlie lower part, as we now look at tliem, is the free jDor- 

 tion of eacli, wliicli alone is visible in the living- fish, the 



SCALES OF COLDFISn. 



other parts being concealed by the three neighbouring 

 scales that overlap it, — above, in front, and below. 



In those from the lateral line, the tube already re- 

 ferred to is seen to pervade each, running through it 

 longitudinally, so that it opens posteriorly on the outer 

 surface, and anteriorlv on the inner or under surface of 

 the scale. In the scales near the front of the line, just 

 behind the head, the tube is large and prominent (a), 

 while in the scales at the opposite extremity it becomes 

 slender ; diminishing, in the very last scale, viz. at the 

 commencement of the tail-fin, to a mere groove. 



The whole surface of each scale, when viewed under 

 a lens of low power, is seen to be covered with concen- 



