A bundle of fibres laid down by the foot of some bivalves, and used by them for attachment; The gape through which it passes is sometimes called the byssal notch or byssal gape.

A bivalve shell is the enveloping exoskeleton or shell of a bivalve mollusc, composed of two hinged halves or valves. The two half-shells, called the "right valve" and "left valve", are joined by a ligament and usually articulate with one another using structures known as "teeth" which are situated along the hinge line.

Byssal notch (or, byssal gap) in a specimen of Arca wagneriana from the upper Pliocene Tamiami Fm. (Pinecrest Beds) of Sarasota County, Florida (collections of the Paleontological Research Institution, Ithaca, NY).

Byssal notch Indentation below anterior auricle of right valve in many Pectinacea (scallops) for passage of byssus (a bundle of hairlike strands used for attachment) or protrusion of foot (a muscular structure for burrowing and locomotion).

Depending on the species and family concerned, some bivalves utilize their inhalant siphon like the hose of a vacuum cleaner, and actively suck up food particles from the marine substrate.

A byssus notch: may be present on a bivalve’s dorsal side, as a shallow indentation or hole to prevent interference: with the opening and closing of the valves.

The Bivalvia is the second most speciose class in the phylum Mollusca. Bivalves are distinctive within the Mollusca in that they are almost always completely enclosed within their shells.

A byssal notch on the right valve just ventral of the auricle includes a series of denticles, forming a structure called a ctenolium that is a synapomorphy of the family. The shell is composed of a combination of aragonite and calcite and coloration is often vibrant.

The most distinguishing feature of a Sentis Scallop is its extremely unequal ears. Each bivalve half has two ears — the front ears are 4-5 times larger than the hind ears. On the lower margin of the right front ear there is a distinct, angled byssal notch. The left …

Bivalves • A pair of calcareous valves that enclose the laterally compressed body • Valves united dorsally by elastic ligament • Bilaterally symmetrical (usually axial plane between the two valves) • Shallow to deep water, marine and fresh water • Most benthic, infaunal or epifaunal • Size: from microscopic to more than 1 meter ...