This book IS an attempt to review the state-of-the-art in the fields of limnology and of marine biology in the Sudan. The need for it became apparent while we were doing some joint field work in the Nile Valley and along the Red Sea coast. We feel that several reasons justify its publication. Firstly, a vast amount of information is being gathered year after year by the staff of the Hydrobiological Research U nit of the University of Khartoum, in conjunction with the faculties of Medicine and Agriculture of this university; much of this information fails to find an outlet to the scientific literature. Secondly, we did not want to restrict our book to the Nile Valley. The Nile is such a vital life artery to the Sudan that it has dominated limnological efforts in this country, to the neglect of other geographical areas. The same holds true for the field of marine biology, which lags far behind, despite the existence of a marine field laboratory at Suakin and a research institute at Port Sudan. It is hoped that both will develop considerably in the near future.

Inhalt
One: General.- 1. The Nile: Description, hydrology, control and utilisation.- 2. Implications of sea mining for the Red Sea environment.- 3. Physical and chemical characteristics of the Blue Nile and the White Nile at Khartoum.- 4. A faunistic reconnaissance of Lakes Kundi and Keilak, western Sudan.- 5. A note on some investigations carried out in the area of the Sudan Plain to be affected by the Jonglei Canal.- Two: Algae and primary production.- 6. A quantitative study of the phytoplankton in the Blue and White Niles at Khartoum.- 7. Primary production and respiration of the phytoplankton in the Blue and White Niles at Khartoum.- 8. Some algae from the Red Sea Hills in north-eastern Sudan.- Three: Macrophytes.- 9. Permanent swamp vegetation of the Upper Nile.- 10. Effects of 2,4-D on mature and juvenile plants of water hyacinth (Eichornia crassipes (Mart.) Solms).- 11. Observations on the effect of the weevils Neochetina eichhorniae Warner and Neochetina bruchi Hustache on the growth of water hyacinth.- 12. Mineral nutrient demands of the water hyacinth (Eichhornia crassipes (Mart.) Solms) in the White Nile.- 13. Ecological observations on mangroves of the Red Sea shores of the Sudan.- Four: Anthropods.- 14. A review of the rotifer fauna of the Sudan.- 15. Bogidiella nubica n.sp. from interstitial waters of the Sudan (Crustacea: Amphipoda).- 16. The occurrence of Limnohalacarus (Acari: Halacaridae) in Lake No, White Nile.- 17. On the freshwater ostracods (Crustacea, Ostracoda) of the Sudan, with special reference to the Red Sea Hills, including a description of a new species.- 18. Cladocera from the Sudan: Red Sea Hills, Jebel Marra and valley of the main Nile.- 19. Nilobathynella predynastica n.g., n.sp. (Crustacea: Bathynellacea) from the Nile valley in Nubia.- 20.Parapseudoleptomesochra attirei n.sp., a new species of Nitocrella from Nubia (Copepoda, Harpacticoida).- 21. Dragonflies (Insecta, Odonata) from the Red Sea Hills and the main Nile in Sudan.- 22. The calanoid copepods of the Nile system.- 23. Food and food selection of the Penaeid prawn Penaeus monodon (Fabricius).- Five: Molluscs.- 24. Ring formation and annual growth in Corbicula consobrina Caillaud, 1827 (Bivalvia, Corbiculidae).- 25. The invasion of Biomphalaria pfeifferi by Schistosoma mansoni miracidia and the development of daughter sporocysts.- 26. Location of Biomphalaria pfeifferi by Schistosoma mansoni miracidia in stagnant and running water under field conditions.- 27. Feeding and growth of the pearl oyster Pinctada margaritifera (L.) in Dongonab Bay, Red Sea.- 28. Aquatic snails of the Jonglei region, southern Sudan, and transmission of trematode parasites.- Six: Fish.- 29. The food and growth of pelagic 0+ Alestes nurse (Characidae) from the Blue Nile, near Khartoum.- 30. Use of the frontal bone in age determination of Labeo horie (Pisces, Cyprinidae) in Jebel Aulia Reservoir, Sudan.- 31. Seasonal abundance, breeding and sex-structure of populations of Tilapia nilotica (L.) and Labeo niloticus (F.) in the Jebel Aulia Dam area of the White Nile.- 32. Aspects of the biology of the catfish Clarias lazera (Cuv. & Val.) related to its economic cultivation.- 33. Fishes and fisheries of Lake Nubia, Sudan.- 34. Gill net selectivity in Lake Nubia fisheries.- 35. Breeding of Barbus bynni (Pisces, Cyprinidae) in Jebel Aulia Reservoir, Sudan.- 36. Food and feeding habits of Labeo niloticus (Pisces, Cyprinidae) in Jebel Aulia Reservoir, Sudan.- 37. On the reliability of the growth rings in two species of the family Characidae in the Sudan.- 38. Adaptive respiratory significance of organophosphates (ATP & GTP) in air-breathing fishes.- 39. Development of dependence on aerial respiration in Polypterus senegalus (Cuvier).