. Elements of zoology, or, Natural history of animals / ed. by Reese. Zoology. CLASS POLYGASTRICA GENERAL DESCRIPTION. 4S5 germs of all these are diffused through the atmosphere in order to account for their appearance in the several situations they frequent), must be regarded as nearest to the truth. It is quite certain that no fluid, the communication of which with the ex- ternal air is prevented, will produce animalcules : and thus it would appear that the invisible germs are sown, as it were, like seeds, in the solution, and are called from their previously tor- pid state into active
. Elements of zoology, or, Natural history of animals / ed. by Reese. Zoology. CLASS POLYGASTRICA GENERAL DESCRIPTION. 4S5 germs of all these are diffused through the atmosphere in order to account for their appearance in the several situations they frequent), must be regarded as nearest to the truth. It is quite certain that no fluid, the communication of which with the ex- ternal air is prevented, will produce animalcules : and thus it would appear that the invisible germs are sown, as it were, like seeds, in the solution, and are called from their previously tor- pid state into active life, by the nutriment they find there, differ- ent kinds of which are adapted to different species of animal- cules. 843. In the class Polygastrica are included all the most minute species of true Animalcules, and some among the larger ones; but as a whole, the beings composing it are smaller than the Rotifera, and far smaller than those of any other class. The largest among them are but with difficulty seen by the naked eye, and of the dimensions of the smallest the mind can scarcely form an adequate conception, although they may be numerically stated. The class takes its name from the belief entertained by the celebrated Prussian naturalist, Ehrenburg (who has devoted almost his whole life to the study of the microscopic forms of existence), that the animals composing it may be characterized by the possession of many distinct stomachs or digestive sacs. There is some doubt upon this question, however; that which can actually be seen will be presently stated, and it will be pre- ferable to enter no further into the question in this place. 844. The bodies of these Animalcules are of very soft con-. Various forms of Animalcules. >. sistence, and very transparent, so that they resemble flakes of very thin jelly. Their forms are extremely variable; and, in some species, the same individual at different times alters its 887. How is their generation accounted for? 888. To what c
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