The freshwater fishes of British Guiana, including a study of the ecological grouping of species and the relation of the fauna of the plateau to that of the lowlands . plateau: 3, 13, 19 = per cent. (2) Found also below the Kaieteur: 10, 20, 22 = per cent. c. Peculiar genera and species. (1) Peculiar to the plateau: 5, 6 = per cent. (2) Found both above and below the Kaieteur, but confined to the Potaro(?): 2, 8 = per cent. A. If this fauna is the nucleus of the original undifferentiated fauna of SouthAmerica we are at once confronted by the fact that per cent, of t
The freshwater fishes of British Guiana, including a study of the ecological grouping of species and the relation of the fauna of the plateau to that of the lowlands . plateau: 3, 13, 19 = per cent. (2) Found also below the Kaieteur: 10, 20, 22 = per cent. c. Peculiar genera and species. (1) Peculiar to the plateau: 5, 6 = per cent. (2) Found both above and below the Kaieteur, but confined to the Potaro(?): 2, 8 = per cent. A. If this fauna is the nucleus of the original undifferentiated fauna of SouthAmerica we are at once confronted by the fact that per cent, of the speciesare identical with species now found everywhere, and per cent, consist ofspecies belonging to genera of the widest distribution in South America. The EIGENMANN: THE FRESHWATER FISHES OF BRITISH GUIANA 101 Rhamdia auelenHelogjenef* marmoratusPygidtum quidncnseCallicMhvs caliichttiyaLithogenes villosusCorvmbophanes andersoniFvrrDulina rtlameritoaaPoec ilobry con bovalliiMcenkhausia oligolepisMcenkhausia brown!Crealocnanes affinisAsfyanax bimacJaTus ? lya alalia HoplervUrinus unitaeniaTus ELrylnnnus yTrinn H oTus caraponoln lypopomus brevirobtriS. Rivulus yEauidenS pofBroensis HeTerogramma orTmanni Grenicrchla alfa Fig. 23. Table showing Distribution of the Fishes taken byC. H. Eigenmann in the Potaro River abovethe Kaieteur Falls. (No. 18a, mentioned in the table above, should have been added. It was overlookedin preparing this figure.) great improbability that so many species should have retained their identity sincethe early tertiary, or should have diverged only in minor specific characters, dis-poses of the theory that this fauna as a whole is the nucleus of the original SouthAmerican fauna. The number of species peculiar to the plateau forms a largerpercentage than a corresponding list for the entire Potaro below the Kaieteur, butnot too large to be readily accounted for by the easy access to the Lower Potaro pos-sessed by all the species of the Essequibo. Su
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Keywords: ., bookauthoreigenman, bookcentury1900, bookdecade1910, bookyear1912
