THE MARINE FAUNA OF THE BLACKWATER ESTUARY 15 Sorby, H. C. (1903). (b) Marine Zoology. Victoria County History: Essex, 1 : 69-88. Walne, P. R. (1956). The biology and distribution of the Slipper Limpet, Crepidula fornicata in Essex Rivers. Fish. Invest., Ser. 2, 20 (6). Wheeler, A. C. (1965). The occurrence of the Blue Whiting in the southern North Sea. Ann. Mag. nat. Hist. (13), 8: 155-159. Wheeler, A. C. & Mistakidis, M. N. (1960). The Skipper (Scomberesox saurus) in the southern North Sea and Thames Estuary. Nature, 188: 334-335. Yonge, C. M. (1960). Oysters. 209 pp. Collins, London. FAUNA LIST The list has been arranged according to the system and nomenclature of the 1957 edition of the Plymouth Marine Fauna with the exception of the Phylum Mollusca which follows the system of Winckworth (1932 and 1951). The records all come from the surveys made by the Central Electricity Research Laboratories and Ministry of Agriculture, Fisheries and Food between 1959 and 1965 unless references given indicate otherwise. Full details of the collections made are included in a series of restricted circulation notes and reports. A type collection of many of the specimens is held by the Central Electricity Research Laboratories. Phylum PROTOZOA Class SARCODINA (RHIZOPODA) Order Foraminifera Elphidiidae Elphidium crispum Linne. Some generally occur in plankton samples but the species is most commonly found in silt or sand on the bottom. Miliolidae Spiroluculina planulata (Lamarck) Recorded once from fine sediments dredged in Swire Hole. Probably common. Miliolina sp. Reasonably common in fine sediments on the bottom. Verneuilinidae Verneuilina polystropha (Reuss) Recorded once from fine sediments dredged in Swire Hole. Probably common. Order Spirotricha TINTINNIDAE Some unidentified members of this family are commonly found attached to small algae on the lower shore.