ON THE OCCURRENCE OF THE PROSOBRANCHS LITTORINA NERITOIDES, L. MARIAE AND L. OBTUSATA IN DENMARK

Littorina neritoides occurs on piers and large stones on thebeaches in northern Jutland, but may not be able to toleratecold winters. L. obtusata and L. mariae are common on Fucus,but only L. mariae penetrates deeply into the fjords and sounds. (Received 10 December 1979;