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蜗牛有几千个牙。谢谢。

(2010-05-23 10:35:46) 下一个
Snails can have hundreds to thousands teeth! Most mollusk groups, including snails (gastropods), have a set of teeth that is shaped like a wavy ribbon called a radula ribbon. Bivalves such as clams, scallops, oysters are the exception and do not have this structure. There can be hundreds of rows of teeth and several different tooth types in one snail or very few rows with a single tooth in each. As the teeth get worn they are continuously replaced by developing teeth, much in the same way that a shark\'s teeth are. These teeth can be used for scraping food such as algae, however, there are snails that have evolved teeth that serve as harpoons which are hollow and used to inject venom when catching prey such as fish. The characteristics of the teeth help scientist distinguish between different species and how they are related to other snail groups.
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