Caudal mucous pit on some species included: 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
Fish fin into flippers), and sea snakes (vertically expanded, flattened tail fin). The use of fins for the propulsion of aquatic animals can be remarkably effective. It has been calculated that some fish can achieve a propulsive efficiency greater than 90%. Fish can accelerate and maneuver much more effectively than boats or submarine, and produce less water disturbance and noise. This has led to biomimetic studies of underwater robots which attempt to emulate the locomotion of aquatic animals. An example is the Robot Tuna built by the Institute of Field Robotics, to analyze and mathematically model thunniform motion. In 2005, the Sea