The prosobranch gastropods Buccinum undatum and Neptunea antiqua from the N.W. Atlantic have been regarded as food generalists, being largely opportunistic feeders upon carrion. However, examination of gut contents shows that polychaetes form about 6O% of the diet of Buccinum, although a wide variety of other prey may be eaten. Neptunea has a more restricted diet and eats mainly bivalves, with polychaetes of lesser importance; although Priapulus formed a major part of its diet at Millport. The diets of these temperate species are broader than those of tropical relatives of similar size, and this pattern of high latitude food generalist and tropical specialist conforms with the general ecological hypothesis which suggests that the temporal heterogeneity of the environment at high latitudes precludes specialization upon a particular food type.