. A textbook in general zoology. Zoology. CLAMS, OYSTERS AND MUSSELS 121 are rare. Oliver Wendell Holmes has made "The Cham- bered Nautilus" the subject of one of his finest short poems. Characteristics and relationships of the mollusks. — All of the members of this branch have soft bodies. With the exception of the slugs, squids, cuttlefishes, and a few others, their bodies are protected by shells which are usually com- posed of one or two valves. The majority of mollusks hve in water and breathe by gills. Some breathe air directly by means of lungs. It is thought that the branch Mo
. A textbook in general zoology. Zoology. CLAMS, OYSTERS AND MUSSELS 121 are rare. Oliver Wendell Holmes has made "The Cham- bered Nautilus" the subject of one of his finest short poems. Characteristics and relationships of the mollusks. — All of the members of this branch have soft bodies. With the exception of the slugs, squids, cuttlefishes, and a few others, their bodies are protected by shells which are usually com- posed of one or two valves. The majority of mollusks hve in water and breathe by gills. Some breathe air directly by means of lungs. It is thought that the branch MoUusca is more closely related to the Annulata than to any of the preceding branches. It is certain that they are the highest animals so far studied. ^'''°- ^^- ^^'"'^ °'' p^'^''^ ''''^*"""- Adaptations to environment. — Perhaps the first adapta- tion to note is the unique one which enables the long clam to live so deep in the mud, out of reach of its enemies above. There it lies six or ten inches deep in the mud, and yet, by means of its long siphons, is able to get a supply of fresh air, water, and food. Although the squids have no outside shell for protection, they have a sac full of pigment by which they can color the water, blind the pursuer, and so escape. The kmg of the pond snail, besides acting as a Imig, serves. 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 Herrick, Glenn W. (Glenn Washington), 1870-1965. New York, Cincinnati [etc. ] American Book Company
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectzoology, bookyear1912
