Monadina.] infusorial animalcules. 137 



latory motion. The animal progressed by leaps, revolving at the 

 same time. 



Genus Teepomonas, (D.) — Animals with a compressed body, thicker 

 and more rounded posteriorly ; with two anterior ciu-ved narrow lobes, 

 each terminated by a flagelliform filament, producing an active 

 whii'ling and jerking movement. 



The examples of this genus are very common in aU collections of 

 marsh water containing decomposing plants, but are most difficult to 

 determine, owing to the ii'regularity of their form and the rapidity 

 of their movements. I have rather glimpsed than certainly detected 

 their flagelliform filaments, and have in vain attempted accurately 

 to delineate them. 



T. affilis. — Body granular, imequal. Length, 1-1 300th. 



Genus Hexamita, (D.) — Animals with an oblong body rounded in 

 front ; constricted and bifid or notched behind. Two to four filaments 

 extend from the anterior border, and the two posterior lobes are pro- 

 longed as two flexuous filaments. 



This genus, characterized by the number of its motor filaments, 

 appears sufiiciently distinct from the preceding. Its species occur 

 in decomposing marsh water, or in the intestine of Batrachians ; but 

 not in artificial infusions. 



H. nodulosa. — Body oblong, with three or four longitudinal rows 

 of nodules, the two lateral of which are extended into tapering 

 slender lobes, each terminated by a filament. Movement vacillating. 

 Length l-1300th to l-1500th. (P. 21. f. 1.) 



H. injlata. — Body oval oblong, rendered almost quadrangular by 

 the processes, giving origin to the filaments. Length 1 -600th — 

 l-1300th. 



H. intestinalis. — Body fusiform, prolonged into a bifid tail, very 

 common in the abdominal cavity of the Batrachia (Frogs and Newts)- 

 It moves in a straight line, oscillating from side to side. 



Genus Hetekomita, (D.) — Animals having globular, ovoid, or oblong 

 bodies, with two filaments extending from the same point in front, 

 one slender undulating, and producing an onward movement, the 

 other thicker, stretching posteriorly, free, or contracting adhesion 

 with the glass slide, so as to cause a sudden movement backwards. 



The several sections of the Monadina, together with the Thecamo- 



L 



