Animals which possess collar cells and an osculum as characteristic features belong to phylum:

Members of phylum Porifera are commonly known as sponges. Sponges have a water transport or canal system. Water enters through minute pores (ostia) in the body wall into a central cavity, spongocoel, from where it goes out through the osculum. Choanocytes or collar cells line the spongocoel and the canals.