General characters of Phylum Arthropoda: (Arthropoda = "jointed foot"). It is the largest group of animals comprising of about 900,000 species. The animals of this phylum are found all over the world in all climates and conditions. Distinguishing characters:
i. The body is metamerically segmented.
ii. The body is jointed outwardly and bilaterally symmetrical.
iii. Typically each segment has a pair of jointed appendages.
iv. Coelomata and triploblastic.
v. A hard, non-living, exoskeleton is present. It is usually made up of chitin.
vi. Body divided into head, thorax and abdomen.