Question

What are the locomotory organs in porifera , cnidaria , plantyhelminthes , and nematoda ?

Answer 1

In porifera, adult sponges are sessile and are commonly attached to surfaces. Some however can create a root-like base and can attach itself to soft sediment. Some poriferan species have been recognized in their ability to move at extremely slow speeds. Commonly, sponges tend to rely on water currents for movement.
Cnidaria move either by the use of floats or sails or by using the medusae form.
Platyhelminthes move either by the use of mesooderm as a hydrostatic skeleton or by other specialized structures such as proboscis, suckers or hooks.
Locomotion in nematodes involves the use of somatic muscles present below the cuticle and hypodermis.