40 INFUSORIA. 



scribed, it is necessary to begin the examination of the animalcule 

 immediately on placing it in coloured fluid, as the deglutition of the 

 coloured particles is very rapid ; frequently, in the course of half a 

 minute the pellets may be seen to issue one after the other from the 

 oesophagus, and to be gradually propelled along the internal wall of the 

 cavity of the animalcule. In Paramecium, Kerona, and the Vorticellce, 

 each new pellet pushes the preceding one before it so that they mount 

 up along the opposite wall and are returned down the other side, until, 

 after having accumulated to some extent, they are expelled one after the 

 other from the anal outlet. 



(82.) The number of pellets thus formed is frequently so considerable 

 that they fill up the whole abdominal cavity, and so closely united to- 

 gether that they form a mass that revolves slowly upon itself, as may be 

 seen in the Vorticellce. This last kind of movement is the effect of the 

 forcible expulsion of the newly-formed pellets from the gullet into the 

 common cavity, of which fact M. Meyen assures us that he has had con- 

 vincing proof. In other cases, when the number of pellets is small, 

 they exhibit the kind of circulatory movement already spoken of, the 

 cause of which is not so obvious. 



(83.) The observations of Dr.Lachmann relative to the mode of feeding 

 of the Acineta (fig. 17) throw considerable light upon this part of their 

 economy. When an Infusorium touches the button-like dilated apex of 

 the ray of an Acineta, it usually remains adhering to it ; the apex of the 

 ray becomes still more dilated, so as to form a sucking disk, and the ray 

 becomes thicker and shorter ; at the same time other rays make grasp- 

 ing movements, and endeavour to attach their extremities, which are 

 dilated into sucking disks, to the captured prey. If the latter does not 

 soon succeed in making its escape by great exertions, by which the rays of 

 the Acinetae are often much disarranged and injured, the Acineta begins 

 to suck out its contents. Each ray is a sucking proboscis ; and it may 

 soon be seen that a current of chyme -particles runs from the alimentary 

 cavity of the captured Infusorium into the body of the Acineta, through 

 the axis of the rays, which, after seizing the prey, have become short- 

 ened and thickened. In the body of the Acineta, the chyme-particles 

 still run at first in a single row, but afterwards they collect in a drop, 

 which soon becomes amalgamated with other drops derived from other 

 suckers. When a considerable quantity of the chyme of the captured 

 animal has passed over into the Acineta, a remarkable change gradually 

 takes place in its appearance : if it was previously pale, nearly trans- 

 parent, and only very finely granulated, larger, dark globules, resembling 

 fat-drops, now make their appearance here and there, and these soon 

 increase, so that the body acquires a granular aspect and becomes 

 opake. The globules or drops which thus make their appearance can 

 only be formed in the body of the Acineta, as they are far larger than 

 the chyme -particles which are seen flowing through the sucker. The 



