n. The integument of the undersurface of the bell, or disk-shaped body, of a jellyfish.
the GNU version of the Collaborative International Dictionary of English
n. The integument of the under surface of the bell, or disk-shaped body, of a jellyfish.
The Century Dictionary and Cyclopedia
n. The internal ventral or oral disk of a hydrozoan, as a jellyfish; the muscular layer beneath the umbrella or swimming-bell of a hydromedusan, continuous with the velum.