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.
Did You Know?
At Lake Itasca, the elevation of the Mississippi River is 1,475 feet above sea level. It drops to sea level at the Gulf of Mexico. More than half of that drop occurs within the state of Minnesota.