The two hoses that Tellins use to suck up mud and pump unwanted mud back out of their shell are called 'siphons'.
You don't often see Tellins. Where do these sand-burrowers spend their time?
Tellins are bivalves. This means that they have two shells, joined by a hinge. Their body is inside the shells. The shells can grow to about 4.5 cm wide. The shells are white and chalky. The shells have a distinct bend at one end.

Tellins live on the southern coasts of Australia. They can be found in muddy sands, in estuaries and among seagrass.
Tellins eat small particles of dead plants and animals. They also eat lichen.
Tellins suck up mud and particles through a small hose that comes out of their shell. They pump the unwanted mud back out of their shell through another hose. They digest any plant or animal matter.
Birds, crabs, octopuses and stingrays all eat Tellins.