Titicaca has long been one of the most widely known of all lakes from its peculiar geographic and historic significance. It is known as the greatest South American lake, as "the Cradle of the Inca Civilization", as the highest navigated lake of the world, or even with greater significance, geographically and biologically, as the center of its own unique plateau basin. The Lake and its environment have allured numerous travelers, impelled by curiosity, or governed by the serious purpose of studying the wonderful ruins of the Cuzco and Titicacan regions or the geology and natural history of that remarkable plateau. Some of these investigators have explored the lake itself to discover its aquatic fauna and flora, but these are the investigators who have had the least return for their labor. Notwithstanding repeated investigations, we know now only of a remarkably restricted fauna and flora. Doubtless, from its peculiar origin, its great elevation, and its isolation. Lake Titicaca has comparatively little to offer to the strictly biological collector. Nevertheless, it may yet have a greater biological interest if it should afford a unique opportunity for the study of problems which bear on the relation of the physical condition of a lake to its animal and plant life. No other fresh-water lake of such a size has so limited a variety of species. Because of the peculiar isolation it has so long endured, its animal and plant forms can only such be as have survived its gradual elevation and transformation from an arm of the sea to a freshwater lake at 12,000 feet; or, perhaps, those which have endured from a later period when, as a great inland sea, Titicaca may have poured its waters into the Amazon -'when the greatest lake of the land fed the greatest river of the world"; or yet, they may be such forms as have been able to pass over the barriers that are ordinarily insuperable.
It would be a study of extreme interest, to make in Titicaca, for comparison with well-known American or European lakes, the exact quantitative Vivien de Saint-I) " L a nappe d'eau l a p l u s remarkable du gloibe". Martin.