PECTORAL FINS. 135 



little pectoral fins; these are moving inces- 

 santly day and night, and carefully as I have 

 watched, I have never yet seen them stop 

 for an instant. A curious result followed 

 from this to the little fish which I hatched in 

 my barrack-room ; the perpetual motion of 

 the fins collected the bits of dust that were 

 floating in the water, and felted them into 

 a regular collar round the fish's throat. 

 Every morning I caught in a spoon the fish 

 which wore this Elizabethan frill a touch 

 of the camel-hair brush, and they slipped 

 away out of their collar as merry as ever 

 again. 



There are, however, certain points in the 

 economy of the young fish which required 

 interpretation by means of the microscope, 

 viz. : first, the gradual absorption of the 



