594 DESCKiPTioN OF {Tolyfjastnca. 



OxYTRiCHA cicada {Trichoda cicada, M.) — Body ovate or almost 

 hemispherical, back furrowed and notched, under surface flat. 

 Found upon the surface of stagnant water. Size 1-I440th to 

 l-860th. 



0. lepus. — Body whitish, elliptical, smooth, flat ; ciliated an- 

 teriorly ; provided with setse posteriorly ; the mouth and discharging 

 orifices not distinct ; Ehrenberg has not seen the male generative 

 apparatus. Found in standing water. Size l-540th to l-96th. 



The following additional species of Oxytricha are given by 

 Dujardin. 



0. incrassata. —Body ovoid, long, colourless, fringed pos- 

 teriorly, with rigid setse. It is not so long as O. pelionella, 

 and unlike it is marine. Length 1 -350th. In Mediterranean. 



0. lingua. — Body diaphanous, flattened, flexible, elongated, 

 rounde'd at each end without setse or apparent cilia posteriorly ; 

 granules of surface in nearly regular rows. Length 1-2 1 2th. In 

 ditch water with Confervse. 



0. amhigua. — Body colourless, oval, oblong, depressed in the 

 middle, concave on one side, margin tumid ; furnished with very 

 strong locomotive ciha, on the concave surface and with rigid setse 

 behind. Length 1 -350th. Found in sea water. 



0. radians. — Body discoid, red, surrounded by long radiating 

 setse. Length 1 -520th. In salt or brackish water. 



Genus Ceratidium. — The horned Animalcules have cilia, horns 

 on the frontal region, but no styles or uncini. But little of their 

 organization is known, and therefore the situation of the species is 

 uncertain. It requires a power not less than 350 to exhibit it. 



C. cuneatum. — Body triangular, front truncated, as also the two 

 horns, upper side smooth. Ehrenberg found this whitish animal- 

 cule in 1820 amongst Conferva, but has not lately seen it. Dujardin 

 believes it to have been a mutilated Oxytricha. It vibrates, runs, 

 and climbs quickly. Figs. 338, 339, represent two views of this 

 animalcule. Size 1 -430th. 



Genus Kebona. — The claw Animalcules are provided with cilia 

 and uncini, but not with styles. The body is soft, flexible, oval 

 and flattened, and ciliated, and has upon the under surface claws, 

 and perhaps setse. Numerous digestive cells indicate the polygastric 



