Page:The naturalist on the River Amazons 1863 v1.djvu/369

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Chap. VII.

FAUNA OF BARRA.

343

the Amazons, so that the great contrast in the forest-clothing of the two rivers cannot arise from this cause.

I did not stay long enough at Barra to make a large collection of the animal productions of the neighbourhood. I obtained one species of monkey; not more than a dozen birds, and about 300 species of insects. Judging from these materials, the fauna appears to have much in common with that of the sea-coast of Guiana; but, at the same time, it contains a considerable number of species not hitherto found in Guiana, or in any other part of South America. The resemblance between the eastern shore of the Rio Negro and the distant coast of Guiana, in this respect, appears to be greater than that between the Rio Negro and the banks of the Upper Amazons.^[1]

The species of monkey mentioned above was rather

↑ My own material is perhaps not sufficient to establish this view of the relations of the fauna, for it requires the comparison of an extensive series of species to obtain sound results on such subjects. A few conspicuous instances, however, pointed to the conclusion above mentioned. For example: in birds, the beautiful seven-coloured Tanager, Calliste tatao, the "sete cores" of the Brazilians, a Cayenne bird, is common to Guiana and the neighbourhood of Barra, but does not range further westward to the banks of the Solimoens; where, from Ega to Tabatinga, the allied form of Calliste Yeni takes its place. The Ramphastos Toco, or Tocano pacova (so named from its beak resembling a banana or pacova), a well-known Guianian bird, is found also at Barra, but not further west at Ega. In Coleopterous insects such species as Aniara sepulchralis, Agra ænea, Stenocheila Lacordairei, and others, confirm this view, being common to Cayenne and the Rio Negro, but not found further west on the banks of the Solimoens. Mr. Wallace discovered that the Rio Negro served as a barrier to the distribution of many species of mammals and birds, certain kinds being peculiar to the east, and others to the west bank (Travels on the Amazons and Rio Negro, p. 471). The Upper Amazons Fauna, nevertheless, contains a very large proportion of Guiana species.

[1] My own material is perhaps not sufficient to establish this view of the relations of the fauna, for it requires the comparison of an extensive series of species to obtain sound results on such subjects. A few conspicuous instances, however, pointed to the conclusion above mentioned. For example: in birds, the beautiful seven-coloured Tanager, Calliste tatao, the "sete cores" of the Brazilians, a Cayenne bird, is common to Guiana and the neighbourhood of Barra, but does not range further westward to the banks of the Solimoens; where, from Ega to Tabatinga, the allied form of Calliste Yeni takes its place. The Ramphastos Toco, or Tocano pacova (so named from its beak resembling a banana or pacova), a well-known Guianian bird, is found also at Barra, but not further west at Ega. In Coleopterous insects such species as Aniara sepulchralis, Agra ænea, Stenocheila Lacordairei, and others, confirm this view, being common to Cayenne and the Rio Negro, but not found further west on the banks of the Solimoens. Mr. Wallace discovered that the Rio Negro served as a barrier to the distribution of many species of mammals and birds, certain kinds being peculiar to the east, and others to the west bank (Travels on the Amazons and Rio Negro, p. 471). The Upper Amazons Fauna, nevertheless, contains a very large proportion of Guiana species.

[1]