232 Dr. C. F. J. Lachmann on the Organisation of Infusoria. 



in the larger species, especially the Acineta ferrum-equinum, 

 Ehrbg.*, is as follows : — 



When an Infusorium touches the button-like or plate-like 

 dilated apex of the ray of an Acineta, it usually remains adhering 

 to it ; the apex of the ray becomes still more extended in the 

 form of a plate, so as to constitute a sucking disk, and the ray 

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

 grasping movements, and endeavour to attach their extremities, 

 which are becoming 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 Acineta are often 

 greatly disarranged and injured, the Acineta begins to suck out 

 its contents. Each ray is a sucking proboscis, and we soon see 

 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 pi'ey, have become 

 shortened and thickened. In the body of the Acineta the chyme- 

 particles still run at first in a slender row, but afterwards they 

 collect in a drop (fig. 14), which, although drops are also formed 

 in the chyme of the Acineta by other suckers, soon becomes 

 amalgamated with these. When a considerable quantity of the 

 chyme of the captured animal has passed over into tlie body of 

 the Acineta, a remarkable change gradually takes place in its 

 appearance : if it was previously pale, nearly transparent, and 

 only very finely granulated (fig. 14), larger, dark globules, re- 

 sembling fat-drops, now make their ajipearance here and there ; 

 and these soon increase, so that the body, which at the same 

 time of course increases in thickness, acquires a coarsely granular 

 aspect, and becomes opake (fig. 15). The globules or drops 

 which 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 f. The animal whose 

 contents are thus sucked out, gradually collapses and dies ; many 

 become liquefied when only a little of the chyme is extracted 

 from them, others still live for a long time; in large animals, 

 such as Stylonychia Mytilus, Paramecium Aurelia, &c., the suck- 

 ing often continues for several hours. Whether the Acinetince 

 possess an anus, or in what way they again throw off effete 

 matters, has not yet been ascertained. 



With regard to the structure, and especially the nutritive 

 apparatus of the Rhizopoda (including besides the Foraminifera 



* This has subsequently been described by Weisse as Acineta cothumata, 

 and by Stein us the diadcm-like Acineta. 



t These alterations in the appearance of the body occur also in other 

 Infusoria when they have devoured animals (Infusoria). 



