Canal system of phylum porifera
| Criterion | Ascon | Sycon | Leucon |
| Complexity | Simplest | Intermediate | Most complex |
| Spongocoel | Present | Present | Absent |
| Radial Canals | Absent | Present | Absent |
| Surface Area | Limited | Increased | Extensive |
| Filtration | Limited | Enhanced | Highly efficient |
| Choanocytes | Lining the spongocoel | Lining radial canals | Lining chambers and canals |
| Water Flow | Direct | Radial | Complex, multidirectional |
| Osculum | Present | Present | Present |
| Examples
| Small, simple sponges e.g Leucosolenia
| Medium sized sponges e.g Scypha (bag sponge)
| Larger, more complex sponges e.g Clathrina
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