182 MICROSCOPY FOR BEGINNERS. 



merged objects, and from which they are easily broken. 

 The latter kinds are readily recognized, being formed of 

 a yellowish brown, transparent membrane, egg-shaped, 

 and with the stem almost equalling their own length. 

 If the observer be fortunate he may see the worm es- 

 cape by pushing off the top of the egg, which falls away 

 like a round cover, leaving an empty case shaped like a 

 deep cup. These empty vases are often found at the 

 bottom of long-standing collections of plants. 



The Turbellarian worms are very common, but the 

 beginner can scarcely hope to learn the generic name 

 of each one that he may find. He will be safe, however, 

 if he refers to them all as Tnrbellarians, or Turbellarian 

 worms. The subject has not been studied very exten- 

 sively by American naturalists, and there is, consequent- 

 ly, nothing in the language to which the beginner can 

 be referred for help. 



The worms are often visible to the naked eye as 

 minute whitish or flesh -colored floating bodies, or as 

 small bits of white thread. There are two forms fre- 

 quently met with which are huge when compared with 

 most of these ciliated creatures, needing no microscope 

 to identify them. Both are found on the lower sur- 

 faces of submerged stones or sticks, or gliding over the 

 sides of the collecting-bottle. 



The body of one of these may be about half an inch 

 in length and about five times as long as broad. It is 

 opaque and almost black. Near the anterior border are 

 two black eyes, which are conspicuous on account of the 



