All sponges obtain their food in the same way, namely by means of the currents of water set up by the Flagella of the collar-cells.
"Freshwater Sponges, Hydroids & Polyzoa"
Nelson Annandale
These Flagella, although apparently there is little concerted action among them, cause by their rapid movements changes of pressure in the water contained in the cavities of the sponge.
"Freshwater Sponges, Hydroids & Polyzoa"
Nelson Annandale
There still remains the difficulty of explaining why the male gametocytes after reduction develop into similar sperms, with their heads and long Flagella, although half of them possess one X chromosome each and the other half none.
"Hormones and Heredity"
J. T. Cunningham