Hieroglyphics of Horapollo, tr. Alexander Turner Cory, [1840], at sacred-texts.com
When they would symbolise a father, or a man who
does not provide for himself, but is provided for by his domestics, they depict A PINNA AND A CRAYFISH; for this crayfish remains adhering to the flesh of the pinna, and is called pinnophylax (protector of the pinna), and acts agreeably with its name. For the pinna when hungry always opens her shell, and when, whilst she lies gaping, any little fish comes within it, the pinnophylax pinches the pinna with its claw, which when the pinna perceives, she closes her shell, and thus catches the little fish.