lOO AQUATIC MICROSCOPY FOR BEGINNERS. 



land the beautiful creatures appear to be more perma- 

 nent denizens of shallow pools, and more frequently 

 collected. 



They have had a varied experience with the sys- 

 tematists, or those scientific men who appear to be 

 happy only when they are arranging the objects of 

 Nature in classes and groups, for these pretty globes 

 have been classified among the plants, then among the 

 animals, and back and forth in a way that, would have 

 bewildered them perhaps, if they had been conscious 

 of it, but certainly in a way to bewilder a reader who 

 has tried to follow the changes to and fro, and tried 

 to get the unfortunate things safely lodged in the 

 one group or the other. At present, they are said to be 

 animals. That is, their latest investigator has so de- 

 cided. By the time this book is out of the printer's- 

 hands V61vox may again be a plant. 



It has been here referred to as a plant and included 



among the plants for convenience, the writer trusting^ 



to the explanation of its vicissitudes to impress the 



reader with the fact that, just now, Volvox is not a 



-plant. 



4. HYDRODfCTYON (Fig. 81). 



A yellowish-green scum is sometimes seen on the wa- 

 ter, which, when spread out over the figures, proves to 

 be a net of delicate hexagonal meshes. It may grow 

 to ten or twelve inches in length, and form floating 

 masses several inches in thickness. The nets are 

 composed of narrow, short, cylindrical cells, and' are, 

 under a low power, remarkably beautiful. The figure 

 shows a part of a net, H. utriculdtum. Fig. 8i. 



In my locality in New Jersey, Hydrodictyon oc- 



