foot
Quick Summary
The foot is a key external feature of mollusks, though its form and function vary greatly across different classes. In its basic form, it is a muscular, glandular, and often ciliated organ used for locomotion.12
In gastropods, the foot can be broad and adhesive, like in limpets, or modified for swimming in pelagic species. Some gastropods also have lateral projections called parapodia, which aid in swimming or are reflexed over the shell.2
Bivalves possess a bladelike, pointed foot adapted for digging. They use their foot to burrow by extending it, gripping the substrate, and retracting it to pull the shell downward. This action, combined with water expulsion from the mantle cavity, helps fluidize sediment for efficient burrowing.3
Mollusks generally move using propulsive waves along the foot's surface, supported by musculature and a hydrostatic skeleton. Some can also jump or twist by flexing their foot. While many mollusks use their foot for crawling or burrowing, some have adapted it for swimming or even for defense, such as by self-amputating a portion to distract predators.42
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gastropodLocomotionThe foot is the organ of locomotion in land gastropods. In swimming and sessile forms, however, the foot is greatly reduced or greatly modified. The normal progression of a snail is by muscular action, with a series of contraction waves proceeding from the posterior to the…
Read MoreThe foot is the organ of locomotion in land gastropods. In swimming and sessile forms, however, the foot is greatly reduced or greatly modified. The normal progression of a snail is by muscular action, with a series of contraction waves proceeding from the posterior to the…
Read More- gastropodThe foot
Although the basic form of the foot is a flat, broadly tapered, muscular organ, which is highly glandularized and usually ciliated, numerous modifications occur in various groups. Frequently there is an anterior-posterior division into a propodium and a metapodium, with the former capable…
Read MoreAlthough the basic form of the foot is a flat, broadly tapered, muscular organ, which is highly glandularized and usually ciliated, numerous modifications occur in various groups. Frequently there is an anterior-posterior division into a propodium and a metapodium, with the former capable…
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locomotionBottom locomotionThe foot of these creeping animals is extremely muscular, penetrated by nerves, and capable of generating one, two, or four laterally adjacent contraction waves. If the foot generates a pair of waves, the lateral halves of the foot may alternate, thereby producing a shuffling movement, or…
Read MoreThe foot of these creeping animals is extremely muscular, penetrated by nerves, and capable of generating one, two, or four laterally adjacent contraction waves. If the foot generates a pair of waves, the lateral halves of the foot may alternate, thereby producing a shuffling movement, or…
Read More- locomotionFossorial invertebrates
…bivalves have a large muscular foot that contains longitudinal and transverse muscles as well as a hemocoel (blood cavity). The digging cycle begins with the extension of the foot by contraction of the transverse muscles. The siphons (tubular-shaped organs that carry water to and from the gills) are closed, and…
Read More…bivalves have a large muscular foot that contains longitudinal and transverse muscles as well as a hemocoel (blood cavity). The digging cycle begins with the extension of the foot by contraction of the transverse muscles. The siphons (tubular-shaped organs that carry water to and from the gills) are closed, and…
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