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 swariiiiii<4- 

 with animal life. iTumensc 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 linos, most of which are seen to be 

 composed of more or fewer beaddike bodies, united into a chain. These occasionally bend 

 themselves, wriggle nimbly, and eft'ect 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 be 

 seen among them briskly wriggling about, which resemble a little coil of spiral wire. Such 

 forms bear the generic appellation of Spirillum.^'' (See engraving, p. G-iG.) 



THE VORTICELLID.E. 



These animals, called Bdl-Animalcidcs, 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 loug cilia, surrounding the anterior extremity, which can bi^ 

 cxserted 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 miniature 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. G46.) 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 

 staik, 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 vorticella 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 allied 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 surfece. 



organizations in the highest state of activity ; and after a variety of practice in waters of all kinds, wc are able to say, 

 that we have not yet tl)und a half-pint of fresh water in any part of the country in which liiere were not more or 

 less animalcules ; and in most water, after standing a few days, they were countless. I?ut of course tiie 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 b}' a 

 thousand-fold. There is scarcely any form of animalcule known to inhabit fresh water which we have not found in. 

 the Croton, with the aid of the microscope."— //(/r/;f;'6' Ma'jazlne, March, ISoii. 



