PROOF FOR AN ENDOGENOUS COMPONENT IN PERSISTENT SOLAR AND LUNAR RHYTHMICITY IN ORGANISMS

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Abstract
Two groups of fiddler crabs of 250 animals each were placed in two wooden buckets two-thirds filled with Fucus, and covers with several holes bored through and a black cloth on the under side. One group was kept at Woods Hole. The other was taken in the cabin of a commercial airlines plane to San Francisco, and by car to the Dept. Zoology, U. of California at Berkeley, where the animals were separated into three pans of sea water and kept in a room with constant light at an intensity of less than 1 ft. c. At the same time the animals at Woods Hole were handled in an identical way. Beginning at 1 p.m. PST (4 p.m. EST) August 18 the state of the chromatophores was determined at hourly intervals for the crabs in the two locations until the pigment was in the night phase. From then on, detns. were made at hourly intervals from 4 to 12 p.m. and 4 to 10 a.m. EST, and from 1 to 9 p.m. and 1 to 7 a.m. PST. The last determinations were made at 10 a.m. EST (7 a.m. PST) on August 24. Comparisons of the times at which the chromatophores of the two groups passed through stage 2.5 showed that on all 5 evenings the California crabs lightened later than the Woods Hole crabs, and for 3 out of 6 morning values they darkened later than the Woods Hole Crabs, the average difference for the 11 transitional points being 22 min. Considering average values for both morning and evening, the Woods Hole and California crabs averaged 38 and 40 min. earlier, respectively, during Aug. 18-20 than their 6-day means, and 49 and 53 min. later, respectively, during Aug. 21-23 than their 6-day means. Reasons are advanced for the conclusion that the difference in the transitional points for the two groups of crabs occurred during the transfer of the one group from Massachusetts to California, indicating that the crabs have an endogenous mechanism marking for off periods of solar and lunar day lengths.