What structure's are used to classify the arthropods?

The arthropods are mainly classified depending upon the appendages present.

The phylum arthropoda is classified in to four subphylums

subphylum: Trilobita (Tri= three; lobita=lobe). The dorsal exoskeleton shows three lobes

subphylum: Chelicerata (Gr., chele= claw + keros=horn+ata=group)

subphylum : Myriapoda

subphylum: Hexapoda

subphylum: crustacea