Caudal mucous pit Caudal mucous pit The caudal mucous pit, or caudal mucous horn, is an anatomical structure on the tail end of the foot of various land snails and slugs, terrestrial pulmonate gastropod mollusks. The function of this pit is the resorption of mucus when the gastropod is moving (see also Muratov 1999). An incorrect and yet often-used term for this structure is the "caudal gland". This area also used to be referred to by the term "caudal pore". Families of snails and slug where a caudal mucous pit exists in every species included: Families/subfamilies where is caudal mucous pit exists only
Fin that "the dorsal and anal fin wakes are rapidly entrained by the caudal fin wake, approximately within the timeframe of a subsequent tail beat". Once motion has been established, the motion itself can be controlled with the use of other fins. Boats control direction (yaw) with fin-like rudders, and roll with stabilizer fins and keel fins. Airplanes achieve similar results with small specialised fins that change the shape of their wings and tail fins. Stabilising fins are used as fletching on arrows and some darts, and at the rear of some bombs, missiles, rockets, and self-propelled torpedoes. These are typically