. Elements of comparative zoology. Zoology. 146 SYSTEMATIC ZOOLOGY. which are in constant motion, and when the animal casts itself loose these serve like so many oars to propel it through the water. At the larger end of the body these hair-like organs become much larger, and they are here arranged in a spiral. The effect of their constant mo- tion is to create a minute whirl- pool in the water, the centre of which is in an opening in the larger end. This may be com- pared to a mouth. The water brings with it minute particles suitable for food, and these pass through the mouth into a cavity com
. Elements of comparative zoology. Zoology. 146 SYSTEMATIC ZOOLOGY. which are in constant motion, and when the animal casts itself loose these serve like so many oars to propel it through the water. At the larger end of the body these hair-like organs become much larger, and they are here arranged in a spiral. The effect of their constant mo- tion is to create a minute whirl- pool in the water, the centre of which is in an opening in the larger end. This may be com- pared to a mouth. The water brings with it minute particles suitable for food, and these pass through the mouth into a cavity comparable to a gullet, from which they pass into the central part of the cell, where they are digested. Then the indigestible portions are at last passed out from the body at a fixed point, the functional V6Ilt- The larS6 cllia alwa^S m°Ve in a ™^™ and rhythmic manner-a fact which would im-. FIG. of a Proto- cZ,° aroTd nervebri£g9: w> nucleus; nr' ply that they were connected and controlled in some manner in their action; and high microscopic powers show at their bases a cord of somewhat denser material which takes the place of a central nervous system. If this be cut, the cilia no longer work in harmony. Finally, all animals, in doing work, produce nitrogenous waste, which must be got rid of by means of kidneys. In the form figured the kidneys. 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 Kingsley, J. S. (John Sterling), 1854-1929. New York, H. Holt and Company
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectzoology, bookyear1904
