Ostium.
The body of a sponge is covered in tiny openings called pores. These pores allow water to flow in and out of the sponge, which helps the sponge filter out food particles and oxygen from the surrounding water.
Small pores of sponges are called ostia through which water enters while a large pore through which water exits is called osculum .
They are called stomata, openings or pores in the epidermis of leaves.
The surface of the orange puffball sponge is covered with small pores that filter small particles of food from the water that passes through them. Each sponge has flagella that help move the water through the sponge.
Stomates =] ♥
sponge
Plants breathe through small openings in their leaves called stromates, which open and close with water availability.
They are called stomata, tiny holes that regulate the intake/output of gas, such as carbon dioxide and oxygen.
stomata stomata
A small sponge.
That would be a porthole, mate.
It's called a bore brush.