Question

....... vascular system is formed in sponges

Answer 1

All the activities of their body of the sponges depend on the current of water entering through ostia and passing out through osculum or oscula. Inside the body, water current flows through system of spaces which collectively constitute the canal system. The entire physiological activities of the animal depend on the water current and the exchanges between the body and the exterior arc maintained through the water current. The food and oxygen are brought through this current while excreta and reproductive bodies are excluded through this current. The perforations of the body of the sponge by a large number of ostia is characteristic of phylum Porifera.

All the living tissues of the sponges are soft and it is a direct need of the animal to maintain a constant shape with different canals or passage-ways. Therefore, deeper layers of the body are provided with supporting spicules. Around the osculum, spicules are long and straight, while spicules situated around ostia are short and straight; around spongocoel they are T-shaped, while triradiate in the body-wall.

Thus, all the cavities of sponges with intricate passages of canals, traversed by currents of water entering by pores and passing out by osculum are collectively termed as a canal system of sponges.

Answer 2

Canal system vascular system is formed in sponges.