No. 2.] FRESH-WATER PROTOZOA. II 



however, be considered in this preliminary report. The waters 

 which have furnished the specimens have been largely drinking 

 waters of Middletown and other cities, although a considerable 

 amount of material has been obtained from brooks and rivers, 

 road-side pools, and even watering troughs. 



THE PROTOZOA. 

 The Protozoa are divided into classes, as follows : 



1. Animals partly free, partly attached, with pseudo- 



podia, flagella, or cilia 2 



Animals, when adult, attached usually by a stalk; 

 the free portion provided with a small number of 

 stiff knobbed projections, which can be withdrawn, 

 called tentacles SUCTORIA p. 65 



2. Adult animals with pseudopodia 3 



Adult animals with flagella or cilia 4 



3. Pseudopodia of variable form; sometimes with a 



shell either homogeneous or made of plates, sand* 



grains, etc RHIZOPODA p. 11 



Pseudopodia stiff, finely thread-like, seldom branched 

 or anastomosing, arranged radially around the 

 spherical body ; sometimes with an envelope of 



jelly, or a skeleton of silicious needles 



HELIOZOA p. 17 



4. With 1-2, rarelv 3-4. long flagella, and one nucleus 



MASTIGOPHORA p. 19 

 With a large number of cilia and one or more 

 nuclei CILIATA p. 39 



CLASS RHIZOPODA. 

 Key to Genera. 



No shell 2 



With a shell 9 



Pseudopodia lobe-like 3 



Pseudopodia fine, reticular, arising in groups 



Gymnophrys 



No nucleus 4 



With nucleus 5 



