. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. MOLTING IN BALANUS AMPHITRITE NIVEUS 115 Periodic fluctuations in shell growth rate were evident in the series grown in con- tinuous light, but not in the series grown in total darkness (Fig. 8), even though they were maintained on the same diet in a constant temperature cabinet. These fluctuations were not evident in B. iinprovisits and the cause in B. amphitrite niveus is not known. Unfortunately, Series VII, reared in twelve hours of light and twelve hours of darkness, and the second series grown in continuous light, Seri
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. MOLTING IN BALANUS AMPHITRITE NIVEUS 115 Periodic fluctuations in shell growth rate were evident in the series grown in con- tinuous light, but not in the series grown in total darkness (Fig. 8), even though they were maintained on the same diet in a constant temperature cabinet. These fluctuations were not evident in B. iinprovisits and the cause in B. amphitrite niveus is not known. Unfortunately, Series VII, reared in twelve hours of light and twelve hours of darkness, and the second series grown in continuous light, Series III, could not be maintained beyond 18 days. Thus sufficient data are not avail- able to allow comparisons between these series and the others. Growth in the laboratory, under the conditions described, was never as rapid as that observed for barnacles grown in the harbor. Mortality In spite of the uniform conditions provided by a culture cabinet, mortality con- tinued to be very high, even though the barnacles were provided with the same diet which furnished the best growth in B. improvisus with practically no mortality 25 r- 20 15 10 5 X. 0 6 7 8 12345 MOLT FIGURE 9. Percentage of mortality in relation to molting in Balani/s ainphitritc nircus. (). The question arose as to whether death could be due to intrinsic condi- tions, a particular time in the life cycle, or a specific period within the molting cycle. Examination of Figure 9 indicates that the greater percentage of mortality occurs during the first two molting periods, followed by a steady decrease in succeeding molts. Mortality of B. amphitrite nvueus in the harbor is also very high, especially during the first week after settling. Records have been kept which show the num- ber of barnacles settled on a plate over a period of a month. These rec- ords include recently settled as well as older individuals for each week of the month. An analysis of plates from June, 1953, indicates that at 5 ft. below mean
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
