Olenoides followed the basic structure of all trilobites — a cephalon (head shield), a thorax with seven jointed parts, and finally a semicircular pygidium.

Conspicuous W-shaped wounds, often partially healed, on Olenoides specimens may be due to predation by Anomalocaris.

[2] Its major characteristics are a large parallel-sided glabella, deep interpleural furrows on the pygidium, and slender pygidial spines, as well as the fact that it is the most common limb-bearing trilobite species in the Burgess Shale.

pygidium) has six axial rings that decrease in size backwards and four or five pairs of rearward pointing marginal spines.

[1] Olenoides serratus is one of about twenty species of which the non-calcified parts are known, due to so-called soft tissue preservation.

Olenellus serratus is the only known trilobite with cerci, uniramous appendages on ventral side of last pygidial segment, and these are shaped like the antennas.