Cetacea

[Sarah]

An order of marine mammals, including the whales. Like ordinarymammals they breathe by means of lungs, and bring forth living youngwhich they suckle for some time. The anterior limbs are changed topaddles; the tail flukes are horizontal. There are two livingsuborders: (a) The Mysticete or whalebone whales, having no trueteeth after birth, but with a series of plates of whalebone [seeBaleen.] hanging down from the upper jaw on each side, thus making astrainer, through which they receive the small animals upon whichthey feed. (b) The Denticete, including the dolphins and sperm whale,which have teeth. Another suborder (Zeuglodontia) is extinct. TheSirenia were formerly included in the Cetacea, but are now made aseparate order.