- Other British and Irish Philine spp. have paler bodies.
- Shells of P. quadrata, P. scabra and P. catena have spirals of sculpture spots, but they are linked as chains.
- Shell of P. pruinosa has spiral and longitudinal striae which form slightly raised dots where they intersect.
- Runcina coronata has brown body, but lacks parapodia, and cephalic shield is fused to the mantle with no visible division line.
Sublittorally on silty sand, and on shells and stones covered in Bugula (polyzoan). Littorally, at low water spring tides among encrusting organisms and sediment on sides of large rocks standing on silty sand, on silty gravel under rocks, and on small stones covered in marine growths. Diet unknown. Spawn  a line of about 200 ova wrapped like a ball of wool within a spherical transparent colourless gelatinous capsule with diameter about 1.5mm. Capsule attached to substrate by gelatinous stalk. Individual egg cases transparent colourless showing whitish embryo with a distinct pitchy spot. Embryos rotate slowly within ova.