The pallial line is a mark (a line) on the interior of each
valve
A valve is a device or natural object that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. Valves are technically fittings ...
of the
shell
Shell may refer to:
Architecture and design
* Shell (structure), a thin structure
** Concrete shell, a thin shell of concrete, usually with no interior columns or exterior buttresses
** Thin-shell structure
Science Biology
* Seashell, a hard ou ...
of a
bivalve
Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...
mollusk
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is e ...
. This line shows where all of the
mantle muscles were attached in life. In clams with two
adductor muscles
The adductor muscles of the hip are a group of muscles mostly used for bringing the thighs together (called adduction).
Structure
The adductor group is made up of:
*Adductor brevis
*Adductor longus
*Adductor magnus
* Adductor minimus This is o ...
the pallial line usually joins the marks known as adductor muscle scars, which are where the adductor muscles attach.
The position of the pallial line is often quite clearly visible as a shiny line on the slightly more dull interior surface of the bivalve shell.
[Huber, Markus (2010). Compendium of Bivalves. A Full-color Guide to 3'300 of the World's Marine Bivalves. A Status on Bivalvia after 250 Years of Research. Hackenheim: ConchBooks. pp. 901 pp. + CD. , at p. 57]
References
Mollusc anatomy
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