Tag: non-chordates

In protozoans, porifers and coelenterates the specialised excretory structures are absent. The excretion in these animals occurs through the general body surface. The contractile vacuoles present in freshwater protozoans are the osmoregulatory structures and regulate osmotic concentration (osmolarity) of the body. Though some ammonia is also lost through contractile vacuoles, but they can not be…