» Its a Round worm
» Long, cylindrical, unsegmented worm.
» Bilaterally symmetrical and triploblastic.
» Alimentary canal is complete in which mouth and anus both are present.
» There is no circulatory and respiratory systems but nervous system is developed.
» Excretion takes place through Protonephridia.
» They are unisexual.
» Most form are parasitic but some are free living in soil and water.
Example - Round worm, like - Ascaris, Thread worm, Wuchereia etc.
1. Enterobius (pin worm/thread worm) - It is found mainly in the anus of child. Children feel itching and often vomits. Some children urinate on the bed at night.
2. Filarial disease is caused by Wuchereia bancrofti.
» It is Annulus body Bearing ring.
» Body is long, thin, soft and metamerically segmented.
» Locomotion takes place through Setae made up of Chitin.
» Alimentary canal is well developed.
» Normally respiration through skin, in some animals it takes place through gills.
» Nervous system is normal and blood is red.
» Excretion by nephridia.
» True coelom is present.
» Both unisexual and bisexual.
Example -Earthworm, Nereis, Leech etc.
» It is Jointed leg.
» Body is divided into three parts - Head, Thorax and Abdomen.
» Body is covered with a thick chitinous exoskeleton.
» Circulatory system is open type.
» Its body cavities are called haemocoel.
» Tracheai, book lungs, body surface are respiratory organ.
» These are mainly unisexual and fertilization takes place inside the body.
Example - Cockroach, prawn, crab, bug fly, mosquito, bees etc.
1. There are six feet and four wings in insects.
2. There are 13 chamber in the Cockroach's heart.
3. Ant is a social animal which reflects labour division.
4. Termite is also a social animal which lives in colony.
5. The main excretory organ of insects are malpighian tubules.
» It is Soft bodies animal.
» All the animals in this group are marine.
» Water vascular system is present.
» There is Tube feet for locomotion, taking food which works as sensation organ.
» Brain is not developed in nervous system.
» There is a special capacity of regeneration.
Example -Star fish, Sea urchin, Sea cucumber, Brittle stars etc.
1. The function of the Aristotle lantern is to chew the food.
2. It is found in sea urchin.