. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 262 H. P. KJERSCHOW AGERSBORG. movements are alternated from "side to side. The lashing of the anterior part of the body from side to side is relatively powerful and a much more rapid progressive movement is effected over that attained by creeping. The undulatory movements employed in swimming start with the head being bent downward and sideways, forming a wave-like twist in the side of the body-wall like that in a blade of a propeller. This wave passes gradually toward the posterior end (Figs. 3-4), and disappears when
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 262 H. P. KJERSCHOW AGERSBORG. movements are alternated from "side to side. The lashing of the anterior part of the body from side to side is relatively powerful and a much more rapid progressive movement is effected over that attained by creeping. The undulatory movements employed in swimming start with the head being bent downward and sideways, forming a wave-like twist in the side of the body-wall like that in a blade of a propeller. This wave passes gradually toward the posterior end (Figs. 3-4), and disappears when the animal makes. FIG. 3. Photograph of Dendronotits gigantcus O'Donoghue in the act of swimming; the head has returned from its bend to the right, and the twist-like wave is shown in the side passing toward the posterior end. the next stroke to the opposite side. When the animal makes a stroke to the right the posterior two thirds is bent so as to form an angle of 45° with the anterior one third. But the posterior part of the body also rotates about 45° from the vertical plane, so that the left side with the foot forms a large wave which sweeps posteriorly, while the anterior part of the body, in front of the wave, is kept vertically. When the animal makes a stroke to the left, the same phenomenon is repeated on the right side. An animal may cover a distance of 30 cm. in a few seconds, making side-strokes of about 45 a minute. The creeping method of locomotion was seldom employed. If the animal was forced to the bottom of the dish, it would attach itself to the substratum and commence gliding along imperceptibly. Close observation brought to light, however, a succession of undu-. 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 Marine Biological Laboratory (Woods Hole, Mass. ); Marine Biological Laborator
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
