What is one of a peculiar kind of cups, or calicles, found upon hydroids of the family Plumularidæ. They contain nematocysts. See Plumularia called?

nematocalyx — One of a peculiar kind of cups, or calicles, found upon hydroids of the family Plumularidæ. They contain nematocysts. See Plumularia. (Webster's 1913.)

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