Arborescent - having the size, form, or characteristics of a tree.
Angular - having a bony structure.
Anterior - located near the head in lower animals.
Aperture - an opening, as a hole, gap, or slit.
Benthos - bottom of sea or lake.
Branchial - a breathing organ, as a gill.
Concentric - having a common center.
Cyst - a capsulelike membrane or certain organisms in a resting stage.
Dorsal margin - referring to the top part of the shell where the hinge is located.
Elongate - long or extended.
Extirpated - locally extinct.
Glochidia - a parasitic larva of certain freshwater mussels with hooks for attaching to a host fish.
Gravid - pregnant.
Homogeneous - of the same or similar nature or kind.
Impoundment - to accumulate (water) in a reservoir.
Incurrent - permitting passage to an inflowing current.
Malacology - scientific study of molluscs.
Mantle - a membrane between the body and shell of a mollusk or brachiopod.
Marsupium - a temporary egg pouch.
Midden - piles of freshly cleaned mussels.
Papillae - a small nipplelike projection.
Postbasal - bottom left of a mussel.
Posterior - situated behind a part or toward the rear of a structure.
Siphon - a tubular organ of aquatic invertebrates, by which water is taken in or expelled.
Sporadic - occuring at irregular intervals, having no pattern or order.
Substrates - a surface on which a plant or animal grows or is attached.
Sulcate - having narrow logitudinal indentations.
Sulcus - a deep narrow furrow or groove.
Tubercles - a nodule or swelling.
Ventral margin - the edge near the belly of a mussel.