Give an account on phylum Arthropoda.

Phylum—Arthropoda

i. Arthropod is an ancient and largest phylum.

ii. Insects, spiders, crabs, shrimps, butterflies, millipedes, centipedes and scorpions belongs to this phylum.

iii. Their bodies have a proper segmentation.

iv. Arthropordates shed “chitin” periodically.

v. The coelomic cavity is filled with haemolymph(blood).

vi. They do not have well defined blood vessels.

vii. This is called open circulatory system.

viii. Small arthropods directly absorb oxygen through their body surface.

ix. Excretion occurs through malphigian tubules and green glands.