OF PROTOZOA. 



161 



of the Protozoa ; yet there are others than Stentor in which this 

 character is more evident ; and that you may see how extended 

 and universal it is, I will place before you several kinds of Infu- 

 sorians with as great a diversity in this respect as it is possible 

 to imagine ; and at the same time will show you that the vari- 

 ous organs in all of these have a common physiognomy, such 

 as might be expected if they belong to the same type. As you 

 are already familiar with one of the higher forms of this group, 

 I mean Stentor, you will the more readily, than at any other 

 time, comprehend the relations of the organs of the highest of 

 them all, if I speak of it first. 



The animal in question is one of the Vorticellae, or bell-shaped 

 animalcules, technically called Epistylls. This diagram (fig. 94) 

 represents a colony, or, I might say, a tree of these 

 little bells tipping the ends of the forked branches. 

 You may find it, along with a multitude of its near- 

 est relatives, clothing the loose roots of trees and 

 shrubs, which project into the fresh-water ditches 

 and pools, as if with a thick mould ; and may 

 recognize it, and distinguish it from 

 other kinds, with the naked eye, by 

 its not contracting and shrinking into 

 a smaller mass when touched. This 

 is owing to the uncontractile, rigid 

 character of the stem and branches 

 (fig. 95, p). The body is, however, 



J 



very mobile, at one time expanding to 

 a broad, slightly oblique, bell-shaped 4 

 figure, and at another, rolling in the " 

 edge (d) of the bell, and assuming a 

 close globular shape, hardly recogni- p\ 

 zable as the active creature of a mo- 

 ment before. This contractility re- F 'g- 95 - 



Fig. 94. Epixtyllx flavicans. Ehr. A single, many-forked colony of Bell-ani- 

 malcules. Slightly magnified. Original. 



Fig. 95. One of the bell-shaped bodies of fig. 94, magnified 250 diameters. 



11 



