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Rh ocean, many hundred miles from land. They are supposed on such occasions to be asleep, but they are very vigilant, and will rarely allow a near approach without disappearing by diving. They remain a long time under water, as might be expected from the volume of their arbitrary lungs, enabling them to retain a sufficient quantity of air, while submerged.

The very peculiarities of conformation, however, which adapt them for swift progression in their own element, render them awkward and almost helpless when out of it. It is only with laborious efforts that they are enabled to shuffle along on land; and if once turned over on their backs, their great width and flattened form prevent their ever being able to regain their natural position.

The flesh of the herbivorous kinds is well known as an article of luxury in this country: to voyagers, however, it fills a much more important position, as it affords a most valuable resource in tropical climates, being abundant, easily kept fresh, and as nutritious as it is agreeable. The eggs of all the species are excellent, and are procured in immense numbers; the albumen, or that part which answers to the white, does not grow hard by the application of heat.

The various species seem to have no settled habitat, but are widely scattered over the whole ocean of the warmer regions of the globe. There are, however, favourite resorts, where they are procured in greater abundance, as low sandy coasts of uninhabited islands, or lonely spots on other shores. Thus in the Atlantic, the Cape Verd Isles, Ascension, and the Isles of the West