A small to medium sized species, ranging from 5-8 mm in length. It is a relatively well pigmented, fast running, woodlouse, with a strongly discontinuous (stepped) pereion-pleon body outline and an antennal flagellum composed of three articles. Thus, it is reminiscent of Philoscia sp., and could be confused with Philoscia affinis Verhoeff. However, the conspicuous orange corners to the posterior angles of the last pereionite (most obvious in live specimens) are characteristic of C. cellaria.
A brief description, with figures, is given by Gregory & Marquis (2019).
Distribution and Habitat
Currently, C. cellaria is known from just two sites on Guernsey, Channel Islands some 4.5 km apart. It is undergoing an expansion of range into north-west Europe aided by human activity and is probably a relatively recent colonist of the Channel Islands. It is, perhaps, just a matter of time before it reaches the south coast of England.
Currently, it has been recorded from a domestic garden (from leaf-litter in a dark damp corner behind a shed) and under a stone at the upper shoreline of a shingle beach (Gregory & Marquis, 2019).