Agraulos is a genus of Solenopleuridae[1] trilobites that lived during the Middle Cambrian in North America and Europe, particularly the Czech Republic.

[4] Arion ceticephalus Barrande, 1846 [5] from the Cambrian Eccaparadoxides pusillus Zone in the Skryje Member of the Buchava Formation, within the Skryje–Tyrovice Basin, Bohemia.

Agraulinae with cephala generally domed; glabella isosceles-trapezoidal, i.e. with truncate front and base angles of the forward-converging lateral margins/flanks more than 15°; occipital ring mesially swollen backwards, with or without a medial node or spine; preglabellar field relatively long (sag.

Thorax of up to 16 segments with first anterior axial rings marked by terrace lines immediately succeeded in some species by rings bearing incipient median nodes or incipient/prominent spines; thoracic segments finely punctate or granulate.

Arionellus quadrangularis Whitfield (1884), originally collected from the mid-Cambrian Braintree Formation at Old Hayward Quarry, Quincy, Massachusetts, US, had previously been assigned to Agraulos by Walcott and others.