two areas. “The geographical distribution of the Trematodæ and Cestodæ, which naturally corresponds to that of their hosts, has up to now been but rarely the subject of research work. The Cestodian genus Linstowia, which is found exclusively in the South American Didelphyidæ (opossums) and in Australian marsupials (Perameles) and Monotremata (Echidna), shows that here also facts have yet to be discovered of great zoögeographical interest.” Wallace says of this affinity with South America (loc. cit. vol. i, p. 400): “It is important here to notice that the heat-loving Reptilia afford hardly any indications of close affinity between the two regions, while the cold-enduring amphibia and fresh-water fish offer them in abundance.”
The same peculiarity is shown by the whole of the remaining fauna, so that Wallace believed that the land connection of Australia-South America, if it existed at all, lay nearer the colder boundaries of these continents. The earth-worms also have not made use of this bridge. Since Antarctica is immediately indicated as the connecting link, and it lies on the shortest route, it is not to be wondered that the South Pacific bridge, proposed in its place by a few authors, which seems the nearest way on a Mercator’s map only, is rejected by nearly all.[1] This second element of the Australian
- ↑ Burckhardt is almost alone in advocating the existence of such a South Pacific bridge from the Devonian to the Eocene, but he does so not on biological grounds, which, as Simroth (“Über das Problem früheren Landzusammenhangs auf der südlichen Erdhälfte,” Geogr. Zeitschr., 7, pp. 665–676, 1901), among others, has shown, cannot be adduced, but only on a geological basis. On the west coast of South America, between southern latitudes 32° and 39°, coarse porphyritic conglomerates are found which were described by previous authors as volcanic, but are considered by Burckhardt to be consolidated beach-pebbles. Since they are replaced further east by sand, Burckhardt concluded that they must represent a
