| Particles are caught in the collar part of the choanocyte cells. |
| Within our current understanding of sponge structure, few authors would homologize the choanocyte epithelium of sponges with the lining of the gut in other animals. |
| Due to the physical structure of the choanocyte chambers and oscular chimneys, water can passively flow through the sponge without the choanocytes actively pumping. |
| Fertilization takes place when a choanocyte fuses with the egg. |
| 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. |
| Reconstitution of the choanocyte chambers and of the canal system follow soon afterward, resulting in a young sponge that is functional and able to grow. |
