Question

How do animals of Porifera differ from animals of Cnidaria?

Answer 1

Porifera	Coelenterata (Cnidaria)
1. They have a cellular level of organisation.	1. They have a tissue level of organisation.
2. Their bodies have a number of inhalent (incurrent) pores or ostia and a single exhalant (excurrent) pore or osculum.	2. Their bodies have only a single opening.
3. Digestion is intracellular.	3. Digestion is both extracellular and intracellular.
4. Muscle and nerve cells are absent.	4. Muscle and nerve cells appear for the first time in coelentrates.
5. Appendages are absent in poriferans.	5. Coelenterates have appendages in the form of tentacles.
6. Poriferans contain the special cells called collar cells or choanocytes.	6. Coelenterates contain the special cells called cnidoblasts which contain nematocysts.