pointed at the posterior extremity. The anterior portion 

 of the body is normally obliquely truncated, from which 

 arise two flagella of unequal length. 



P. elongata (Fig. 6) is fairly common in all waters of 

 ponds and bogs, particularly among sphagnum, though 

 it seems never to occur in crowded cultures. 



ORDER HETEROMASTIGIDA 



Gents Klvirea Parona. 



The body is pear-shaped, and though it may elongate 

 and contract slightly during swimming, it is quite stable 

 in form. Of the three flagella which arise from the ante- 

 rior extremity, the stouter, shorter one vibrates forward, 

 and is the organ of locomotion. The other two trail 

 behind. 



E. cioncB (Fig. 7) is apparently not a very common spe- 

 cies. It was found sparsely in the clear cold waters of 

 springs and creeks. 



Genus Dinomonas Kent. 



Members of this genus resemble those of the preeedinir 

 one in the general shape of the body, but they are larger 

 and possess but two flagella, both of which extend for- 

 ward from the more acute anterior extremity. The con- 

 tractile vacuole is usually clearly visible and located in 

 the rounded posterior region. 



Fig. 8 was found abundantly in the scums of various 

 infusions of grasses and leaves, and conforms to the D. 

 vorax of Kent. D. tuberculata (Fig. 9) was often found 

 in the same infusions with D. vorax. It is possible that 

 this may be merely another form of the latter species. 



Genus Pleuromonas Perty. 



Body either kidney-shaped or ovate, the two long fla- 

 gella arising from a depression in the venter which is not, 

 however, invariably present. 



P. jaculans (Fig. 10) is often very common in stagnant 

 waters wherever there is decomposing vegetable matter 



