12 



the minute particles of which the thin film formed upon the surface 

 of the water consists, whether of the drawing-room vivarium, or the 

 exposed pond. After the lapse of some minutes, this being collected 

 into a very minute but appreciable mass, is passed by a central 

 fiirrow, to which a vibratory motion is imparted, upwards to the 

 mouth, and swallowed with apparent relish. These animals are not 

 purely phytophagous, but may frequently be seen hovering round the 

 remains of dead sticklebacks «nd other small fish, with evidently 

 more than mere regard for their memories. 



The abbreviations used in the foregoing list, Lin. and Drap., refer 

 to the works of Linnaeus and Drapamand. 



