CLASS I. INFUSORIA: ORDER 2. ASTOMATA. - 647 
whole fluid becoming turbid, and slightly tinged with green. If now we take, with the point 
of a quill or a pin, a minute drop of the liquid, and examine it with a good microscope 
under a magnifying power of two hundred diameters, we discover the water to be swarming 
with animal life. Immense multitudes of minute round or oval atoms are present, which move 
rapidly with a gliding action. These are animals of the genus Monas. Among them we shall 
probably see other bodies more minute, resembling short lines, most of which are seen to be 
composed of more or fewer bead-like bodies, united into a chain. These occasionally bend 
themselves, wriggle nimbly, and effect a rather rapid progression in this manner. The scum, or 
transparent pellicle, is found to be composed of countless millions of these latter, congregated 
about as thickly as they can lie into patches. They constitute the genus Vibrio ; several may bo 
seen among them briskly Avriggling about, which resemble a little coil of spiral wire. Such 
forms bear the generic appellation of S])ir ilium. (See engraving, p. 646.) 
THE VORTICELLIDiE. 
These animals, called Bell- Animalcules, on account of the shape of some of the species, present 
phenomena as remarkable as any in the history of animated nature. They are characterized by 
the possession of a fringe of rather long cilia, surrounding the anterior extremity, which can be 
exserted and drawn in at the pleasure of the creature ; by the vibration of these cilia the little 
animal, which usually has somewhat the appearance of a ininiature wine-glass, supported upon a 
very long stalk, can produce a sort of vortex in the water, by which smaller animals and minute 
floating particles of alimentary matter are drawn into the mouth. (See engraving, p. 646.) Some 
of these little creatures are furnished with a horny case for the protection of their delicate bodies, 
whilst others are quite naked. 
The genus Vorticella, from which the name given to the family is derived, consists of animals 
of the latter description. Each of these little creatures is placed at the top of a long flexible 
stalk, the other extremity of which is attached to some object, such as the stem or leaves of an 
aquatic plant. This stem, slender as it is, is nevertheless a hollow tube, through the entire 
length of which runs a muscular thread of a still more minute diameter. When in activity, and 
secure from danger, the little vorticella stretches its stalk to the utmost, whilst its fringe of cilia 
is constantly drawing to its mouth any luckless animalcule that may come within the influence 
of the vortex it creates ; but at the least alarm the cilia vanish, and the stalk, with the rapidity 
of lightning, draws itself into a little spiral coil. But the vorticeha is not wholly condemned 
to pass a sort of vegetable existence, rooted, as it were, to a single spot by its slender stalk ; its 
Creator has foreseen the probable arrival of a period in its existence when the power of loco- 
motion would become necessary, and this necessity is provided for in a manner calculated to 
excite our highest admiration. At the lower extremity of the body of the animal, at the top of 
its junction with the stalk, a new fringe of cilia is developed ; and when this is fully formed, 
the vorticella quits its stalk, and casts itself freely upon its world of waters. The development 
of this locomotive fringe of cilia, and the subsequent acquisition of the power of swimming by 
the vorticella, is generally connected with the propagation of the species, which, in this and 
some of the alHed genera, presents a series of most curious and complicated phenomena. 
ORDER 2. ASTOMATA. 
This includes the Mouthless Infusoria^ which appear to be nourished entirely by the absorp- 
tion of fluid matters through their outer surface. 
orgaDizations in the highest state of activity; and after a variety of practice in waters of all kinds, we are able to say, 
that we have not yet found a half-pint of fresh water in any part of the country in which there were not more or 
less animalcules ; and in most water, after standing a few days, they were countless. But of course the most crowded 
residences of the animalcule world are in standing water and exposed streams, on which the sun shines. And although 
Croton water is more free from them than a cistern of rain-water, yet it contains more than ordinary well-water by a 
thousand-fold. There is scarcely any form of animalcule known to inhabit fresh water which we have not found ia 
the Croton, with the aid of the microscope." — Harpers' Magazine, March, 1869. 
