CILIATED ANIMALCULES, 



21 



the mouth, in which position they are always most evident, pro- 

 duce by their vibration currents in the surrounding water, which 

 bring to the mouth smaller animalcules or particles of vegetable 

 matter that may be floating in the neighbourhood thus insuring 

 an abundant supply of nutriment which, without such assistance, 

 it would be impossible for these living atoms to obtain. The food 

 thus procured is at once swallowed, and accumulates in little 

 pellets in the interior of the semi-fluid substance of their bodies, 

 giving rise to an appearance which misled Ehrenberg to suppose 

 that these tiny organisms were possessed of numerous stomachs : 

 hence they were formerly named P.ofygastria 9 *or many-stomached 

 animalcules. 



FlG. IJ. S\VA. \-.\E IK AND ITS Dl 



_ 



FIG. 14. COLEPS AND CHILO.MONAS. 



By no means the least remarkable part of the nistory of the 

 Infusoria is their mode of propagation. This is usually accom- 

 plished by the spontaneous division of the adult animalcule into 

 two or more portions, each of which in a short time becomes in 

 every respect a complete individual. We remember in our boyish 

 days hearing of some strange machine for grinding old people 

 young again, and smiled at the idea little thinking that the con- 

 version of old animals into young ones was, in sober truth, one 



r i 



ot the commonest operations of Nature. The body of an animal- 

 cule about to propagate in this manner, becomes at first slightly 

 elongated, and a line, more transparent than the rest, is seen to 

 cross its middle portion ; a constriction next becomes apparent 

 at each extremity of the line indicated, which, becoming more 

 decided and growing gradually deeper, at length divides the 

 animalcule into two halves, only connected with each other by a 

 narrow isthmus, and as this gets thinner and thinner, a slight 



* TroXi's, polus, many ; yaarep, yaarpos, gaster, gastros, tJit stomacJi. 



