. Adventures with animals and plants. Biology. Fig. 79 The horny, rough tipper surface of a C07HV1071 starfish. What kind of synnnetry has it? (AMERICAN MUSEUM OF NATURAL HISTORY) help in locomotion. Some of them are brightly colored and are very beautiful in structure. If you live near the sea, you are surely acquainted with starfish, sea urchins, and perhaps sand dollars. In tropical waters the beautiful sea lilies, which you might well mistake for plants, grow attached to the sea bottom. All of these are spiny- skinned invertebrates. The starfish. The starfish lives in salt water near the s
. Adventures with animals and plants. Biology. Fig. 79 The horny, rough tipper surface of a C07HV1071 starfish. What kind of synnnetry has it? (AMERICAN MUSEUM OF NATURAL HISTORY) help in locomotion. Some of them are brightly colored and are very beautiful in structure. If you live near the sea, you are surely acquainted with starfish, sea urchins, and perhaps sand dollars. In tropical waters the beautiful sea lilies, which you might well mistake for plants, grow attached to the sea bottom. All of these are spiny- skinned invertebrates. The starfish. The starfish lives in salt water near the shore. It is not a true fish, of course. It is a living flexible star with five arms and a spiny covering colored brown or red or purple. Hundreds of tiny tube feet with suction cups at their ends dot the lower surface of the animal. By pulling in and pushing out the many tube feet in succession the starfish moves along slowh' and smoothly. These tube feet help in breathing, too, and in food getting. By folding itself over an oyster and at-. FiG. 80 The sea urchin has a beautifully marked shell beneath these spines. (American museum OF NATURAL HISTORY) taching its tube feet it pulls the shell open. Then it turns its stomach inside out and digests the living oyster in its shell. Starfish do much damage by feeding on mollusks. Oystermen formerly tried to destroy starfish by tearing them in half and throwing the pieces back into the sea. Unfortunately, this made the situation worse, for new parts similar to those lost will grow back, or regen- erate, making two animals where there had been but one before. Some starfish relatives. Similar to the starfish group but sufficiently different to be put in another class are the sea urchins and sand dollars. They, too, have their mouths on the lower side. They take in sand, in which thev find small animals and plants which arc their food. The sand dollar has a circular flattened shell somewhat thickened in the middle. The sea urchin is so c
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Keywords: ., bookcentury1900, bookpublisherbostondcheath, booksubjectbiology
