  We show how the treatment of cellularity in families of algebras arising from
diagram calculi, such as Jones' Temperley--Lieb wreaths, variants on Brauer's
centralizer algebras, and the contour algebras of Cox et al (of which many
algebras are special cases), may be unified using the theory of tabular
algebras. This improves an earlier result of the first author (whose hypotheses
covered only the Brauer algebra from among these families).
