174 MARVELS OF POND-LIFE. 



tube was carefully held just over him, the finger re- 

 moved, and* luckily in went the little gentleman with 

 the ascending current. He was cautiously transferred 

 to Wenham's Compressorium, an apparatus by which 

 the approach of two thin plates of glass can be 

 regulated by the action of a spring and a screw; 

 and just enough pressure was employed to keep 

 him from changing his place, al though he was able to 

 move his tiny limbs. Thus arranged, he was placed 

 under a power of two hundred and forty linear, and 

 illuminated by an achromatic condenser,^ to make the 

 fine structure of his gizzard as plain as possible. It 

 was then seen that this curious organ contains 

 several prominences or teeth, and is composed of 

 nuiscular fibres, radiating in every direction. From 

 the front of the gizzard proceed two rods, which 

 meet in a point, and are supposed to represent the 

 maxillae or jaws of insects, while between them is 

 a tube or channel, through which the food is 

 passed. The mouth is suctorial^ and the two horny 

 rods, with their central piece or pieces, are pro- 

 trusile. They were frequently brought as far as the 

 outer lips, (if we may so call the margins of the 

 mouth,) but we did not witness an actual protrusion, 

 except when the lips accompanied them, and formed 



* The achromatic condenser is a frame capable of supporting 

 an object glass, lower than that employed for vision, through 

 wiiich the light passes to the object. Tlie appearances mentioned 

 can be seen v\ithout it, though not so well. 



