DESCRIPTION OF FRONTISPIECE. 



The large object in the middle is a Stentor ])olj- 

 morphus, magnified one hundred and five diameters; 

 hanging from the top are Vorticellae, magnified about 

 sixty diameters; on each side at the bottom are Polyps, 

 (Hydra viridis and vulgaris,) the latter having pro- 

 duced by budding a young one as large as herself. 

 These are slightly magnified, the natural size of the 

 objects in fine specimens similarly extended, measures 

 about half an inch. The border is composed of Ana- 

 charis alsinastrum, a weed often prolific in microscopic 

 forms. 



