Phylum- Mollusca :
- Body - soft and slimy.
- Second largest phylum in animal kingdom.
- Aquatic or terrestrial.
- Most - marine, few- fresh water dwellers too.
- Triploblastic, eucoelomate, non-segmented and soft.
- Bilateral symmetry, Except animals like snail.
- Their body is divided into three divisions like head, foot and visceral mass.
- Visceral mass is covered with mantle. This mantle secretes a hard, calcareous shell.
- This shell may be external or internal or even absent in some cases.
- Unisexual.
Examples: Bivalve, Snail, Octopus, etc.
Phylum- Echinodermata :
- Calcareous spines are present on the body of these animals.
- Found only in ocean.
- Triploblastic, eucoelomate.
- Radially symmetrical in adult stage.
- Show bilateral symmetry in larval stage.
- They perform locomotion with the help of tube-feet.
- Tube feet are also useful for capturing the prey. Some animals are sedentary.
- Have skeleton made up of calcareous spines and / or ossicles (plates).
- Good ability of regeneration.
- Mostly unisexual.
Examples: Star fish, sea-urchin, brittle star, sea-cucumber, etc.