Four functional filaments of the freshwater crayfish Cherax tenuimanus (Decapoda: Parastacidae)

A detailed description of the 4th podobranch of the marron Cherax tenuimanus is given, describing four filaments distinguished by their apical morphology: rounded, pointed, alar, and hooked. Four response patterns of these filaments to silver staining (3 minutes in 0.25% solution of AgNO3 and then exposed by immersion in Kodak developer for 30 seconds) were recognized: 1) staining filaments with an unbroken film of stain along the length, 2) non-staining filaments without stain response, 3) mottled filaments had patches of staining along the length of the filament, 4) mosaic filaments which stained in rosette patterns.