Consider following features: Organ system level of organisation...

Organ system level organization, bilateral symmetry, true coelomates with the segmentation of body are seen in Annelida, Arthropoda, and Chordata.

Annelids possess metameric segmentation.

Arthropods have segmented bodies, like the annelids. These segments have become specialized, however, with one pair of jointed appendages added to each segment. Among living arthropods, the millipedes most closely suggest what the ancestral arthropod might have looked like.

Chordates use heteromeric segmentation in which the link between segmented parts appears more subtly.