reproduction fenland morphology waterway bivalvia unionidae dorsal shell
unio dorsally biology halves hinged ventrally
anodonta unionidae martens described zmb species japonica
bivalves bivalve fossil shells
brachiopods brachiopod clam hinge bivalves shells valves line fossils vs symmetry fossil two comparison between clams attached kentucky lines other
lingula arrangement ventral dorsal sides ventrale musculature
scallop shell shells bivalve notch dorsal hinge ventral features structures museumwales naturalhistory ac morphology edge marine margin science july britishbivalves