Canal System:
All sponges marine or freshwater possess in their bodies different pores (Ostiua) and channels through which water from outside enter inside the body after traversing the whole body. It performs various physiological functions and is expelled through a large opening Osculum is collectively called Canal System.
Types of Canal System:
The canal system in sponges ranges from simple grade to highly complex form. The complexities have developed due to the folding of walls of the simplest forms and the restriction of choanocytes in restricted areas. Whatever may be the architectural complexities of the canal system of sponges can be resolved into three main types namely –
- Asconoid type
- Synconoid type
- Leuconoid type