Question

In most simple type of canal system of Porifera, water flows through which one of the following ways?

• A. Ostia $ \to $ Spongocoel $ \to $ Osculum $ \to $ Exterior
• B. Spongocoel $ \to $ Ostia $ \to $ Osculum $ \to $ Exterior
• C. Osculum $ \to $ Spongocoel $ \to $ Ostia $ \to $ Exterior
• D. Osculum $ \to $ Ostia $ \to $ Spongocoel $ \to $ Exterior

Answer 1

Answer: (A)

The ascon type is the simplest type of canal system found in asconoid sponges like Leucosolenia. The course of water current in ascon type of canal system looks like $ \text{Ingressing}\,\text{water}\xrightarrow[\text{Ostia}]{\text{Trough}}\text{spongocoel} $ $ \xrightarrow[\text{Osculum}]{\text{Through}}\text{To}\,\text{outside} $