. Annual report of the Board of Regents of the Smithsonian Institution. Smithsonian Institution; Smithsonian Institution. Archives; Discoveries in science. -•^^^'-sssis:^^*^^**^"*'*^'^^' ^*SSSS5sss; Fig. 7.—A seal in a swimming posture. (After P. Gervais.) The first and fiftli toes of the liind feet are of equal length ; the middle toe is the shortest. The hind flippers are contracted and therefore in the position they assume after a back stroke. The fore llippers serve only for steering, the slightest similarity Avitli those of whales and sea-cows. In swim- ming, they are tnrned about in
. Annual report of the Board of Regents of the Smithsonian Institution. Smithsonian Institution; Smithsonian Institution. Archives; Discoveries in science. -•^^^'-sssis:^^*^^**^"*'*^'^^' ^*SSSS5sss; Fig. 7.—A seal in a swimming posture. (After P. Gervais.) The first and fiftli toes of the liind feet are of equal length ; the middle toe is the shortest. The hind flippers are contracted and therefore in the position they assume after a back stroke. The fore llippers serve only for steering, the slightest similarity Avitli those of whales and sea-cows. In swim- ming, they are tnrned about in a peculiar fashion like a screw. The walrus moves in the water in such a manner that both fore and hind flippers serve in locomotion. The fore flippers move alternately, as in sea-lions and turtles. The hind flippers, on the contrary, are turned about in the same manner as in seals. The swimming mo- tion of the walrus is, therefore, en- tirely different from that of the sea - lions and seals. The tail is rudimentary in all three families of pinnipeds, and plays no role in locomotion. The dentition of the seals is simplified. It serves for masticating food onl}^ in the walrus. In all other pinnipeds, it serves for grasp- ing. Speaking generally, the molar teeth of the seal are serrate, with sharp cutting cusps, while those of the eared seal are single-pointed. Fig. 8.—Eared seal lying on land. (After W. Haacke.) The fore limbs, which serve as propellers, are formed like the wings of Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Smithsonian Institution. Board of Regents; United States National Museum. Report of the U. S. National Museum; Smithsonian Institution. Report of the Secretary. Washington : Smithsonian Institution
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