. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 246 K. S. COLE AND D. L. GILBERT another made in open water. \Ve now report these two observations as a footnote to Packard's paper. In the summer of 1936, H. J. Curtis and K. S. C. saw L. pcalci feeding on "shiners" near a shore of Long Island Sound. As they attacked from below, some squid broke the surface and a few cleared it by an appreciable fraction of their length. Assuming a length of 25 cm, it was guessed that the center of gravity rose 20 cm (/?). From v~ = 2 gh the initial velocity (V) was 200 cm/sec. Th
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 246 K. S. COLE AND D. L. GILBERT another made in open water. \Ve now report these two observations as a footnote to Packard's paper. In the summer of 1936, H. J. Curtis and K. S. C. saw L. pcalci feeding on "shiners" near a shore of Long Island Sound. As they attacked from below, some squid broke the surface and a few cleared it by an appreciable fraction of their length. Assuming a length of 25 cm, it was guessed that the center of gravity rose 20 cm (/?). From v~ = 2 gh the initial velocity (V) was 200 cm/sec. The corresponding figure of 4 knots has often been used as an illustration of the squid jet power and now the agreement with the maximum found for L. vulyaris (Packard, 1969) shows that guesses can be lucky. During work at Montemar, Chile, in 1964, D. L. G. made a movie (Fig. 1) from a small boat of Dosidicus yiyas in a leap above water. Guessing a mantle length of 4 feet it was no great surprise to get an emerging speed of about knots. However, this figure increased to a maximum velocity of almost 14 knots between frames 8 and 9, Figure 2. Frame 12 of Figure 1 and the graph of Figure 2 suggest that a continuing ejection of water produced this acceleration. This example provides a striking illustration of amphibious jet propulsion. u z < I— co ir UJ tr. 9 - 09 HORIZONTAL DISTANCE PER SQUID LENGTH FIGURE 2. Plot of the caudal end of the squid (in Figure 1) in air with respect to the point of origin of the emergence from the water surface, as estimated from the film record. LITERATURE CITED PACKARD, A., 1969. Jet propulsion and the giant fibre response of Loligo. 875-877. Nature, 221 :. 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 Labor
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