Search results
Results From The WOW.Com Content Network
Siphons in molluscs are tube-like structures in which water (or, more rarely, air) flows. The water flow is used for one or more purposes such as locomotion, feeding, respiration, and reproduction. The siphon is part of the mantle of the mollusc, and the water flow is directed to (or from) the mantle cavity. A single siphon occurs in some ...
Because of the expanse of the contracting cavity, the animal's velocity fluctuates as it moves through the water, accelerating while expelling water and decelerating while vacuuming water. Even though these fluctuations in drag and mass can be ignored if the frequency of the jet-propulsion cycles is high enough, jet-propulsion is a relatively ...
The siphon sucks in water to the mantle cavity, and may be long enough to extend through the substrate in burrowing species. In one amphibious group, the Ampullariidae , the mantle cavity is divided into two, with a unipectinate gill on one side, and a lung on the other, so that these snails can respire using air or water.
In certain groups of carnivorous snails, where the siphon is particularly long, the structure of the shell has been modified in order to house and protect the soft structure of the siphon. Thus the siphonal canal is a semi-tubular extension of the aperture of the shell through which the siphon is extended when the animal is active.
The depth, −d, of the initial entry point of the siphon in the upper reservoir, does not affect the velocity of the siphon. No limit to the depth of the siphon start point is implied by Equation 2 as pressure P A increases with depth d. Both these facts imply the operator of the siphon may bottom skim or top skim the upper reservoir without ...
They are marine filter feeders with a water-filled, sac-like body structure and two tubular openings, known as siphons, through which they draw in and expel water. During their respiration and feeding, they take in water through the incurrent (or inhalant) siphon and expel the filtered water through the excurrent (or exhalant) siphon.
This is not a form of active pumping: the gas moving into the chamber is a passive process. Most energy is expended through the absorption of water from the chamber. Removing water from the chambers of the shell reduces the overall density of the shell, and thus the shell behaves as a flotation device comparable to the swim bladder in bony fish.
This siphonal opening also serves for the exit of the water that has entered by the branchial opening. The siphonal notch is a noticeable notch situated at the most posterior part of the aperture of the shell, through which the siphon is extended when the animal is active. The notch at the posterior end of the aperture is also called the anal ...