Completar frases poriferansVersión en línea Complete the text por Rocío Mancilla Romero 1 organs both atrium feeders water move filter sessile Skeleton choanocytes poriferans osculum nervous pores marine Poriferans Sponges , also known as , are the most primitive members of the animal kingdom . Their cells are not organised into well - defined tissues and have no . Most sponges are animals which may form colonies or live as solitary organisms . Sponge are : They attach themselves to the ocean floor and can't around . Poriferans bodies Sponges lack symmetry and have an irregular shape . Their bodies are full of ( which is where the group name comes from ) , through which can circulate . They have a central body cavity ( ) and an upper opening ( ) They have an internal that protects them . It can be composed of rigid spines called spicules , or of flexible fibres , called spongin . Vital funtions of poriferans Nutrition : Sponges are - . The movement of the flagella on creates a flow of water that circulates through the body . Reproduction : Spores reproduce asexually and sexually . Asexual reproduction occurs through fragmentation or gemmation . In sexual reproduction they produce larvae which have the ability to swim . Interaction : Poriferans have no system or sense organs .