• Mississippi National River and Recreation Area


    National River & Recreation Area Minnesota

Mussel Glossary

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?

Headwaters of the Mississippi

The Mississippi River is approximately three feet deep at its headwaters at Lake Itasca and has an average surface speed of 1.2 miles per hour.