This document describes the anatomy of a mussel by labeling its external and internal parts, including the hinge, siphons, mantle, foot, and various muscles. It also notes differences in the shape and positioning of muscles between mussel species found in California versus the Bay.

1. Mussel Dissection

2. Hinge
Anterior
Posterior
Dorsal
Ventral
Byssus
Excurrent
Siphon
Incurrent
Siphon
Posterior adductor muscle (shell closers)
Mussel Dissection

3. Hinge
Mantle edge (secretes shell
and is sensory)
Mantle surface (containing
outgrowth of gonad)
Incurrent
and
excurrent
siphons
Mussel Dissection

4. Byssus Foot Palp
Visceral
mass
Right gill (filaments separated)
Left
gill
Mussel Dissection

5. Parts mussel

6. Hinge
Posterior adductor
muscle (shell closer)
Foot retractors
Mantle attachment scarTiny anterior adductor
muscle (shell closer)
Mussel Dissection

7. Posterior adductor & retractor
muscles elongate, thin (California)
Anterior adductor
muscle on ventral
edge (Bay)
Mussel Dissection
Anterior adductor
muscle centered
(California)
Posterior adductor & retractor muscles
shortened, wide (Bay)
Muscle scars on shell distinguish Bay from
California mussels