The body of a porifera or sponge is organised in such a manner as to form a complex system of pores and canals. This system is called canal system. Three types of canal systems are found in sponges:
(i) Asconoid canal system - It is the simplest type of canal system which is found in Leucosolenia and a few other sponges.
(ii) Syconoid canal system - It is more complex than the ascon type. It is found in Sycon and some other sponges.
(iii) Leuconoid canal system - It is the most complex canal system which is found in Spongilla and some other sponges.