INFUSORIA. 401 



great portion, perhaps a third, of the excluded parts was 

 devoured. 



As soon as the depredators were gone, or even before, 

 others more diminutive, but more numerous, were ready 

 to take their place. The drop of water under review had 

 been found amazingly full of a small oval Monas, perfectly 

 transparent, of an oval form, with some granules visible in 

 the interior. They were about ^V^tti of an inch in length. 

 They filled the whole field, gliding about very nimbly, but 

 so close as but just to allow space for motion, and that in 

 several strata. By the morning these were collected in 

 masses, which to the naked eye looked like little undefined 

 white clouds, but which under the microscope showed the 

 Monads in incalculable multitudes, but for the most part 

 in still repose. Some were seen moving to and fro, how- 

 ever, and, in the course of the day, most of them became 

 again active. As soon as the Colepes had forsaken their 

 prey, the Monads began to gather round it, cleaving to the 

 same parts, and apparently imbibing the juices, for the 

 extruded parts still slowly decreased, until at length these 

 were reduced to about one-third of their original di- 

 mensions. 



A close examination of these latter when they had 

 settled to rest showed me that they were of the species 

 Chilomonas parametrium. There is an indentation on one 

 side of the front where the mouth is situated : here there 

 is a ciliary action ; the projecting part, called the lip, is 

 said to be furnished with two slender flexible proboscides, 

 but my power was not sufficient to discern any trace of 

 these. A sort of a ridge, or keel, runs down the length of 

 the body, perceptible by a slight line ; numbers of stomach- 

 cells also are perceptible. The motion of these lip-monads 

 was not very rapid when unexcited ; it is performed by a 

 sort of lateral half-roll, the two sides alternately being 

 turned up, like a boat broadside to a swell, and the line of 

 progression is undulating. 



D D 



