This paper gives an account of a survey of the invertebrate populations (omitting Protozoa) of eight species of seaweeds on Church Reef, Wembury Bay, extending over the entire intertidal range.
Above high-water neaps the faunas are poor, except for that in Lichina pygmaea which is the richest in individuals on the shore.
Between high-water neaps and low-water springs the most numerous groups are copepods, acarines, young littorinids and (in Ascophyllum only) ostracods.
In the holdfasts of Laminaria digitata polychaetes are very abundant and make up the majority of the population.
The intertidal faunas are compared with those in the soil on land, and prove to be far more abundant. Even the most plentiful group in the soil, the insects, is rarely as numerous as it is in Ascophyllum around mean sea-level.
Altogether 177 species are recorded, of which 35 are not in the Plymouth Marine Fauna (1931).