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 (no͞o′mə-stōm′, nyo͞o′-)
A small opening in the mantle of a pulmonate gastropod through which air passes.

[From New Latin pneumostoma : pneumo- + Greek stoma, mouth.]
References in periodicals archive ?
This caused the snails to open up their pneumostome (breathing tube) to get oxygen from the air.
When the snail opened its pneumostome at the surface, it was given a gentle poke with a wooden stick, causing it to close again.
Tactile stimulation of the lips, tentacles, mantle edge, and pneumostome effectively produces geotactic responses.