| These cells, called choanocytes, resemble independent animals of the Protozoa, known as flagellate Infusoria or Choanoflagellata. |
| Sponge choanocytes also have a flagellum and possess a collar of filaments for trapping food. |
| The choanocyte then transforms into an amoeba-shaped cell called a carrier cell, which gives up the spermatozoan to an egg, lying near a chamber formed by choanocytes and containing long lashlike appendages called flagella. |
| In sexual reproduction, spermatocytes develop from the transformation of choanocytes, and oocytes arise from archeocytes. |
| And a patch inside one of the tubes has pits encircled by raised collars, resembling cells called choanocytes that move water through sponges. |
| Due to the physical structure of the choanocyte chambers and oscular chimneys, water can passively flow through the sponge without the choanocytes actively pumping. |
