Yellowish form with slightly swollen tubercles which resembles A. proxima  as first described by Alder and Hancock from specimens found in the Mersey Estuary. More recent examination of specimens from further afield shows geographical variation in the dominant colour and degree of swelling of the tubercles, though their “obtusely pointed top, not flatly rounded” appears to be a consistent feature.This specimen from Strangford Lough, Northern Ireland. April 2006. © B. Picton.