Depending on the species, either all four gills, only the outer gills, or specialized parts of the gills are used as brood chambers. Conglutinants Packets of glochidia that females of several mussel species release. The various shapes, sizes, and colors of conglutinants attract host fishes. Gills Large sheet-like organs that play a dual role in respiration and feeding. The cilia help to circulate water and capture food particles.
Ciliary tracts move the food to the palps, which surround the mouth.
While they develop into glochidia, the fertilized eggs are also retained inside the gills of the female. Glochidia Microscopic larval stage of the freshwater mussels. Shaped like the adult mussel with two valves but with a different internal structure. Hookless glochidia that attach to the gill filaments of fishes and hooked glochidia that attach to the fins or scales of fishes. A third, less common type is axe-headed with a flaired valve margin.