Macla, a genus of bivalve molluscs, with somewhat triangular equal-valved shells. They are active animals, ploughing their way through the sand either on the shore or at slight depths, and are able like cockles to take considerable leaps. Two common North American species, M. solidissima and M. ovalis, known as hen-clams, surf- clams, &c., are sometimes eaten, while some small
British species—e.g. M. subtruncata—are said to be gathered for feeding pigs.