Conches
Labrosones (or lip-reed instruments)
Hornbostel - Sachs
Tubular labrosones
The air itself is the vibrator in the primary sense. The standing waves are significantly confined within the instrument itself. The air-stream passes through the player's vibrating lips, so gaining intermittent access to the air column which is to be made to vibrate. The instrument has no extra devices to alter its pitch.
Natural labrosones