Class 11 NEET Biology Structural Organisation in Animals

(b) : Pheretima posthuma is highly useful and beneficial in agriculture. Its habit of burrowing and swallowing earth makes it porous and increases the soil fertility in many ways. Their burrows permit penetration of air and moisture in porous soil and their excretory wastes and other secretions also enrich soil by adding nitrogenous matters to the soil. Pheretima posthuma is not used as fish meal. Whereas a small white earthworm (Enchytraeus albidus) is often grown in soil and used to feed aquarium fish.