166 



THE AMERICAN NATURALIST 



[Vol. LI 



Eolophrya sp., scleral 

 Holostichia vernalis, severa' 

 Monas fluida, abundant 



Other forms present in less numbers (fe^ 



Colpidium striatum Oxytrichia hi f aria 



Dileptus gigas Phacus sp. 



Enchelys sp. Paramoecium caudatum 



Epiclintes radiosa Stylonychia mytilus 



Englena viridis Stylonychia pustulata 



The identification of the Monas species (Fig. 11) is very 

 difficult. Members of this genus resemble some of the 

 members of the genus Bodo. Because of the hyaline char- 

 acter of the body its outline is not easy to distinguish. I 

 have found that the most successful method of treatment 

 before identification is attempted, is staining with a strong 

 aqueous solution of iodine and potassium iodide. This 

 both kills and stains. Examination must be made almost 

 immediately since the organisms begin to lose their char- 

 acteristic form in a short time. 



Within the genus Holophrya have been provisionally 

 placed a number of forms very closely allied in general 

 characters. For a considerable number of these a separa- 

 tion into species has not yet been made. 



The pseudopodia of the Mastigamoebae (Fig. 12) do not 

 invariably disappear with the appearance of the flagellum. 

 They often remain, though much diminished in size, and 

 even exhibit appreciable movement. Such movement, 

 however, does not appear to aid in locomotion. 



Enchelys (Fig. 13) is very like Holophrya (Fig. 14) 

 and only under the most favorable conditions of staining 

 and lighting can the side opening buccal orifice be defi- 

 nitely located. The proboscis-like projection at the an- 

 terior extremity of the body is subject to considerable 

 modification, and can not be relied upon as a distinguish- 



