258 POPULAR HISTOUY OF THE AQUARIUM. 



pebbles we do not exactly know, but his actions look very 

 much as if he were rummaging for minute insects and Crus- 

 tacea, wliich have taken refuge between them. He appears 

 resolved hterally to leave no stone unturned to get a liv- 

 ing. I have only once witnessed liim in the act of seizing 

 larger prey, and then it was an unfortunate Planorhis or 

 Flat-coiled Water-Snail. Lt first the D^ficus seemed to 

 be roaming about in quest of something, first under, then 

 over, the leaves of a Water-lily. At last, in a rather dark 

 corner, he seemed to perceive suddenly a Planorbis which 

 was browsing upon the stem of a plant just under the 

 shade of a broad leaf. He darted at this, seized it, and 

 then putting his tail out of water, apparently for the pur- 

 pose of taking in a fresh supply of air, moved slowly down, 

 bearing the Snail with him. He held it, as represented in 

 Plate XIX., by his fore feet, turning round the coil until 

 the aperture of the shell was opposite his mandibles, when 

 he began nibbling away at the animal. In vain did the 

 poor Mollusc try to withdraw within his shelly fortress, for 

 the Beetle picked off the edges of his shell bit-by-bit, so 

 as to expose the body as fast as it was withdrawn. iVll 

 the way down to the bottom of the tank was this pro- 

 cess continued, air-bubbles rising to the top, and bits of 



