. The animal creation: a popular introduction to zoology. Zoology. 230 ROTIFERA. s])in round, and yet preserve their connexion with the animal, they could not conceive. Better instru- ments, however, and closer observation, have solved the difficulty. Instead of being real revolutions of wheels, it is now clearly established that the ap- parent rotations are merely an optical illusion, similar to that by Avhich, when the tide is rollino- in. Fig. 176.—skeleton- wheel bearer. upon the beach, the waves appear to the eye to move rapidly forward, while, as is well known, they merely rise and fall
. The animal creation: a popular introduction to zoology. Zoology. 230 ROTIFERA. s])in round, and yet preserve their connexion with the animal, they could not conceive. Better instru- ments, however, and closer observation, have solved the difficulty. Instead of being real revolutions of wheels, it is now clearly established that the ap- parent rotations are merely an optical illusion, similar to that by Avhich, when the tide is rollino- in. Fig. 176.—skeleton- wheel bearer. upon the beach, the waves appear to the eye to move rapidly forward, while, as is well known, they merely rise and fall in constant succession. The true ex- planation of the once mysterious phenomenon is as follows :—Examined under high powers, the cilia have the appearance of moving in waves, in the production of which from a dozen to twenty cilia are concerned, the highest point of each wave being formed by a cilium extended to its full length, while the lowest point between every tw^o waves is occu- pied by one folded down upon itself, the intervening space being filled by others in every intermediate degree of extension. As the continuance of each cilium in any one of these positions is of the shortest possible duration, and each takes up in regular sue-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Jones, Thomas Rymer, 1810-1880. London : Society for Promoting Knowledge
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Keywords: ., bookauthorjo, bookcentury1800, bookdecade1860, booksubjectzoology
