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 dimensions of the bigger Whales are probably due to the fact that measurements have been taken, not in a straight line from snout to tail, but along the bulging sides of the Cetacean, rendered even more convex than in nature by decomposition, and by pressure due to the immense tonnage of the creature.

The Cetacea are the most perfectly aquatic of all mammals; they never leave the waters which they inhabit. It is true that legends have represented them as pasturing upon the shore—Aelian spoke of Dolphins basking in the sun's rays upon the sand; and the "Devil Fish" of California, Rhachianectes (see p. 357) has given rise to improbable stories—but they are apparently only legends. Indeed a stranded Whale cannot live long, for it is unable to breathe, the comparatively feeble breast being crushed by its own weight. In accordance with the purely aquatic habit, we find a modification of the outward form of the body (and as we shall see later of many of the internal organs), which renders the Cetacea externally unlike all other mammals. The form is fish-like, the fore-limbs are paddles, the tail is expanded into two horizontal flukes, which serve to propel the creature through the water.



The skin is smooth and shiny, so smooth and so shiny that it has often been compared to coach leather. But nevertheless they are not entirely without that most essential character of the class Mammalia, a coating of hair. The hairy covering is, however, reduced to the very smallest proportions; it is represented