 In all three types of structure the cross-section area of the choanocyte-lined regions is much greater than that of the intake and outlet channels.This makes the flow slower near the choanocytes and thus makes it easier for them to trap food particles.For example, in "Leuconia", a small leuconoid sponge about tall and in diameter, water enters each of more than 80,000 intake canals at 6 cm per "minute".