INFUSORIA. 401 



left it, a 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 Jlonas, perfectly 

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

 the interior. They were about -joVo °^ an ^ nc ^ ^ n 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 unde- 

 fined 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, however, 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 dimensions. 



A close examination of these latter when they had 

 settled to rest showed me that they were of the species 

 Chilomonas iKiramozcium. 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 pro- 

 boscides, 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. 



2 D 



