. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. MOON o. MOONlQ B FIGURE 2. Orientation in sequential photographs of two groups of amphipods. A: 16 July I960, 0144-0158 hours, with 30 amphipods; B: 6 August 1960, 2201-2214 hours, with 24 amphi- pods. Arrows within circle (unit radius) represent average direction and scatter of orienta- tion ; numbers associated with arrows indicate sequence. "P" indicates direction of photoflash; "C" indicates "correct" orientation direction relative to "N," north. sibility that the shift is due to s
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. MOON o. MOONlQ B FIGURE 2. Orientation in sequential photographs of two groups of amphipods. A: 16 July I960, 0144-0158 hours, with 30 amphipods; B: 6 August 1960, 2201-2214 hours, with 24 amphi- pods. Arrows within circle (unit radius) represent average direction and scatter of orienta- tion ; numbers associated with arrows indicate sequence. "P" indicates direction of photoflash; "C" indicates "correct" orientation direction relative to "N," north. sibility that the shift is due to some normal compensation for changes in lunar position. Furthermore, the shift apparently does not take place without photogra- phy : qualitative continuous observation of a group of unphotographed amphipods, kept in the observation chamber for 15 minutes, indicated no noticeable orientation shift. (2 September 1960, 2315-2330 hours: lunar day 12; lunar azimuth 206°-210C ; estimated orientation azimuth, initial and final, about 340°; angle with the moon, about 130°.) The results in Figure 2 seem best interpreted as a resetting effect of light on a rhythmic system, a phenomenon previously demonstrated using similar milli- second electronic flashes2 (Pittendrigh, in press). The lengths of vectors in 2 See Pardi and Papi (1953, pp. 466-467) for an alternative explanation of a superficially similar result with solar 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 Laboratory (Woods Hole, Mass. ). Annual report 1907/08-1952; Lillie, Frank Rattray, 1870-1947; Moore, Carl Richard, 1892-; Redfield, Alfred Clarence, 1890-1983. Woods Hole, Mass. : Marine Biological Laboratory
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
