In most simple type of canal system of Porifera , water flows through which one of the following ways ?
Ostia --> Spongocoel -> Osculum --> Exterior
Spongocoel --> Ostia --> Osculum --> Exterior
Osculum --> Spongocoel --> Ostia --> Exterior
Osculum --> Ostia --> Spongocoel --> Exterior
As we have learned
Ascon type canal system -
It is the simplest type
Water ostia
spongocoel
osculum
outside.
- wherein
Eg. Leucosolenia
Simplest type is Ascon type canal system