62 EVENINGS AT THE MICROSCOPE. 



parts, just like tlie finger of a glove, ^"hen the ani- 

 mal ■would again protrude its eye, the fibres wliich sur- 

 round the tentacle, like so many rings throughout its 

 whole length, successively contract, and thus gradually 

 squeeze out, as it were, the inverted Dart, until it is 

 turned back to its original position. 



STBCCTTEE OT ETE IN SNAIl. 



But the ears of this homely " creeping thing " are, 

 perhaps, even more curious than its eyes ; though far 

 less elaborate in their structure. You will imagine 

 now, that I refer to the other pair of tentacles, as you 

 are accustomed to associate the idea of ears with pro- 

 jecting organs situated on the head. Xo, you must not 

 look there for them. Here, in this young Garden Slug, 

 which is so small as to be convenientlv examined on 

 tlie stage of the microscope, and so devoid of colour that 

 we can readily look through its tissues, — we shall easily 

 find its ears, though they are not quite so prominent as 

 those of an ass. 



I subject the animal to a gentle pressure by means 

 of the compressorium, just suflicient to flatten its soft 

 body a little, without injuring it. And now, with this 

 low power, you may see that Siebold, a learned zoolo- 

 gist and comparative anatomist, familiar with the curi- 

 ous phenomena of life, truly calls "• a wonderful spec- 

 tacle." In the neck of tlie little animal vou discern, 



