Читать книгу Parasitology - Alan Gunn - Страница 45

The Parazoa are organisms that lack true tissues. This group contains either only the phylum Porifera, better known as the sponges, or two phyla, the Porifera and the Placazoa depending upon one’s taxonomic preferences. All sponges are aquatic and gain their nutrition through filter feeding and, in some cases, in a symbiosis with algae or bacteria. Sponges belonging to the family Clionaida bore into the shells of molluscs and penetrate the calcareous skeleton of corals (Mote et al. 2019). Other sponges will, in their turn, exploit the burrows and also grow over them. Some workers refer to this as parasitism, although this is debatable.