CONTENTS Introduction................... 3 The generic name................. 4 The type species of Hypostomus Lacépède.......... 6 The identity of Acipenser plecostomus Linnaeus........ 9 The distribution and habitats of the Surinam species........ 12 The relationship of the Surinam species............ 17 Some physiographical data on Surinam waters.......... 21 Collecting localities................. 25 Collecting and collections................ 26 Measurements and methods............... 26 Miscellaneous remarks................ 28 The Surinam species................. 29 Key to the Surinam species............... 30 Descriptions of the Surinam species etc............. 31 Acknowledgements................. 72 Summary ................... 73 References................... 73 Addendum................... 77 Diagrams................... 80 INTRODUCTION The imminent realization of the so-called "Brokopondo Project", first put forward in 1950, and involving the establishment of a barrage and hydroelectric plant in the Surinam River at Afobaka, eventually induced members of the Stichting Natuurwetenschappelijke Studiekring voor Suriname en de