. Animal locomotion or walking, swimming, and flying : with a dissertation on aëronautics. Ftg. 33.—The Porpoise {Phoccena communis). Here the tail is principally en-gaged in swimming, the anterior extremities being rudimentary, and resem-bling the pectoral fins of fishes. Compare with fig. 30, p. 65.— Fig. 34.—The Manatee Ma tiatus A i In this the anterior extremities are more developed than in the porpoise, hut still the tail is the great organof natation. Compare with fig. 33, p. 73, and with fig. 30, p. 65. The shapeof the manatee and porpoise is essentially that of the fish.—Ori
. Animal locomotion or walking, swimming, and flying : with a dissertation on aëronautics. Ftg. 33.—The Porpoise {Phoccena communis). Here the tail is principally en-gaged in swimming, the anterior extremities being rudimentary, and resem-bling the pectoral fins of fishes. Compare with fig. 30, p. 65.— Fig. 34.—The Manatee Ma tiatus A i In this the anterior extremities are more developed than in the porpoise, hut still the tail is the great organof natation. Compare with fig. 33, p. 73, and with fig. 30, p. 65. The shapeof the manatee and porpoise is essentially that of the fish.—Original. the only difference being that the tail acts from above down-wards or vertically, instead of from side to side or anterior extremities, which in those animals are com-paratively perfect, are rotated on their long axes, and appliedobliquely and non-obliquely to the water, to assist in balanc-ing and turning. Xatation is performed almost exclusively bythe tail and lower half of the trunk, the tail of the whaleexerting prodigious power. It is otherwise with the Bays, where the hands are princi- 1 Vide Remarks on the Swimming of the Cetaceans, by Dr. Murie,Proe. Zool. Soc, 1865, pp. 209, 210. 74 ANIMAL LOCOMOTION. pally concerned in progression, these flapping about in thewater very
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