. Comparative zoology, structural and systematic. For use in schools and colleges. Zoology. 50 COMPARATIVE ZOOLOGY. by the vibration of minute hairs, or ciha, lining the ca- nals. The microscopic Infusoria have cilia surrounding the mouth, with whicli they draw or drive into the body little currents containing nutritious particles. Bivalve shells, as the Oyster and Clam, are likewise dependent upon this method of procuring food, the gills being fringed with cilia. So the singular fish, Amphioxus (the only example among Vertebrates), employs ciliary action to obtain the infusorial organisms on
. Comparative zoology, structural and systematic. For use in schools and colleges. Zoology. 50 COMPARATIVE ZOOLOGY. by the vibration of minute hairs, or ciha, lining the ca- nals. The microscopic Infusoria have cilia surrounding the mouth, with whicli they draw or drive into the body little currents containing nutritious particles. Bivalve shells, as the Oyster and Clam, are likewise dependent upon this method of procuring food, the gills being fringed with cilia. So the singular fish, Amphioxus (the only example among Vertebrates), employs ciliary action to obtain the infusorial organisms on which it feeds. The Greenland Whale has a mode of ingestion somewhat unique, gulping great volumes of water into its mouth, and then straining out, through its whalebone sieve, the snuill animals which the water may contain. (2) Solids.—When the food is in solid masses, whether floating in water or not, the animal is usually provided with prehensile appendages for taking hold of it. The jelly- like ximoeba has neither mouth nor stomach, but extemporizes them, seizing its food by merely applying its soft body to it, and then wrapping itself around it. ,„ ,. T. ^ Other minute creatures (Fora- PiG. 14.—A Ehizopod (RoMm Veneta), _ _ _ ^ with psendopodia extended, X 30. miuifcra) extemporizc amis by throwing out thread-like prolongations of their bodies (pseudopodia), which adhere to their prey, and then con- tract. A liigher type is seen in Polyps and Jelly-fishes, which liave hollow tentacles around the entrance to the stomach (Fig. 194). These tentacles are contractile, and, nu)re- over, are covered with an immense number of minute sacs, in which a highly elastic filament is coiled np spiralh'. AVhen the tentacles are touched by a passing animal, as a Crab, they seize it, and at the same tnoment throw out their myriad filaments, like so many lassos, which increase. Please note that these images are extracted from scanned page images that may have been digitally enhanced for
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Keywords: ., bookcentury1800, bookdecade1880, bookpublishe, booksubjectzoology
