The Ecology of Plants and Animals in the Intertidal Regions of the Zwartkops Estuary, Near Port Elizabeth, South Africa

V. THE INTERTIDAL ANIMAL COMMUNITIES .. 361 The lower reaches: .. 361 Fauna of solid substrata . 361 Fauna of sand and mud banks . 364 The Epifauna . 364 (i) Supralittoral fringe .. 365 (ii) Midlittoral zones and infralittoral fringe 366 (a) Spartinetum . 366 (b) Zosteretum . . .366 The Infauna . .. 367 (i) Communities living in clean sand . 368 (a) Calianassa community . .369 (b) Other sand communities . .370 (ii) Communities living in mixed soils and in mud 372 (a) Upogebia community . .372 (b) The species of Cleistostoma . 374 (c) Alpheus community . 374 The middle reaches: . 375 Fauna of solid substrata . 375 Fauna of banks of sandy mud and mud . 376 The upper reaches: . . . .376 Fauna of solid substrata .. 376 Fauna of muddy sand . 377 The Epifauna . . . .377 VI. NUTRITIONAL RELATIONSHIPS . . . . . . 377 VII. BIOTIC FACTORS INFLUENCING DISTRIBUTION . . . 379 VIII. COMMENSALISM . . 380 IX. ZONATION ON THE MUD FLATS AND SAND BANKS . . .381 SUMMARY . . . . .385 REFERENCES . . . . . 385