H. Marguerite Webb

INTERACTIONS OF DIURNAL AND TIDAL RHYTHMS IN THE FIDDLER CRAB, UCA PUGNAX

1. Locomotor activity of the fiddler crab, Uca pugnax, was recorded in constant illumination following a variety of light regimes and in natural illumination.2. When pre-treatment caused a shift in the phase relations of the diurnal rhythm, a shift of activity peaks with respect to time of low tide was also observed; the shift in phase of the tidal rhythm was about the same number of hours as that of the diurnal rhythm.3. Under recording conditions of constant illumination the rate of progression of activity peaks showed systematic variations such that periods calculated for a few days would range from 24.0 hours to 25.8 hours. The apparent period was a function of the phase of the diurnal rhythm in which the peak occurred.4. When recording was carried out under conditions of natural illumination, the tidal rhythm showed a consistent 24.8-hour period.5. The imposition of a 24.75-hour cycle by four-hour supplemental light periods yielded an apparent period of about 25.5 hours for 11 successive days. This i...

ADAPTATION OF THE MAGNETORECEPTIVE MECHANISM OF MUD-SNAILS TO GEOMAGNETIC STRENGTH

1. The maximum orientational response of the snail, Nassarius, to an abrupt experimental reversal of the horizontal vector of geomagnetism occurs when the reversed field deviates least in strength from the earths horizontal 0.17-gauss one.2. The responsiveness to field-direction change drops off very substantially even before the field strength has decreased to 0.1 gauss or increased to 0.4 gauss. It is already minimal at 0.8 gauss.3. The receptor mechanism for compass orientation in response to geographic direction is, therefore, exquisitely adjusted to the strength of the horizontal vector of geomagnetism, even in contrast with the total strength of geomagnetism.4. There is a persistent effect of experimental magnetic fields deviating in strength from the natural one which remains for at least three to five minutes following removal of the experimental field.5. Following exposure to reversed horizontal fields stronger than the earths, southbound snails respond in the earths field by clockwise turning...

A PERSISTENT DIURNAL RHYTHM OF CHROMATOPHORIC RESPONSE IN EYESTALKLESS UCA PUGILATOR

1. The responses of the black chromatophores of Uca pugilator as observed in legs autotomized and maintained in sea water are described.2. The pigment in legs from normal animals in the day (dispersed) phase becomes concentrated after isolation; that from normal animals in the night (concentrated) phase remains concentrated.3. The pigment in legs isolated from eyestalkless animals disperses in the daytime and fails to disperse when the legs are removed from 8 P.M. to 2 A.M.4. The activity on eyestalkless animals of a series of concentrations of eyestalk extract was determined in the daytime and at night. Four of the six concentrations tested were found to be more effective in the daytime than at night.5. The results clearly demonstrate the existence of a diurnal rhythm in eyestalkless animals and that the structures of the eyestalk are not necessary for this rhythm.6. The data provide strong evidence that a black-pigment-concentrating substance participates in the regulation of the chromatophore system of...

A COMPASS DIRECTIONAL PHENOMENON IN MUD-SNAILS AND ITS RELATION TO MAGNETISM

1. Mud-snails in a uniform field of all ordinarily controlled directional factors distinguish among geographic directions.2. Geomagnetism is involved in this directional sense. This was shown by rotation of a 5-gauss horizontal magnetic field which produced an orientational behavior correlated with that observed when the snails were rotated in the opposite direction in the earths field.3. The response pattern to compass directions of the 5-gauss horizontal field was essentially the mirror-image of that observed for the earths 0.17-gauss field.4. The directional response of the snails in the geographic field, and the concurrent correlated response to a rotating experimental magnetic field, vary parallelly with time and with influence of other, still undefined factors.5. Rotation of a 5-gauss horizontal magnetic field through the series of four compass directions, differing by 45° from the four cardinal directions, may produce a pattern of compass-directional behavior either paralleling or mirror-imaging ...

EYESTALK REGULATION OF MOLT AND VITELLOGENESIS IN UCA PUGILATOR

1. The condition of the ovaries of intact and eyestalkless Uca pugilator from Florida was examined throughout the period from mid-September to the end of May. The frequency of molt for the animals was also observed.2. Ovarian weights for intact crabs decreased from September to December and began to increase in January. The increase did not occur uniformly throughout the population, and by March all stages of maturation were present. First oviposition occurred in April, involving about 30% of the females. No oviposition occurred as late as mid-September.3. Crabs that oviposited in April did not exhibit further vitellogenesis prior to molt which occurred in late May. A high frequency of molting again occurred in intact crabs in November and December.4. Removal of eyestalks led to initiation of vitellogenesis in immature ovaries at all times tested and also appeared to increase the rate of vitellogenesis in already maturing ovaries.5. Removal of eyestalks increased the frequency of molt maximally in Septemb...

Temperature-Independence of the Frequency of the Endogenous Tidal Rhythm of Uca

GREENSPAN, E.; LEHMAN, I.; GRAFF, M. N.; and SCHOENBACH, E. B. 1951. A comparative study of the serum glycoproteins in patients with parenchymatous hepatic disease or metastatic neoplasia. Cancer, 4:972-83. LEVER, W. F.; GURD, F. R. N.; UROMA, E.; BROWN, R. K.; BARNES, B. A.; SCHMID, K.; and SCHULTZ, E. L. 1951. Chemical, clinical, and immunological studies on the products of human plasma fractionation. XL. Quantitative separation and determination of the protein components in small amounts of normal human plasma. Jour. Clin. Investigation, 30:99-111.

THE REPETITION OF PATTERN IN THE RESPIRATION OF UCA PUGNAX

1. The form of the mean diurnal rhythm of O2-consumption of Uca pugnax is described and found to be practically identical for the summers of 1955, 1956, and 1957.2. The mean lunar-day rhythm of O2-consumption is described for the summers of the same three years. The curve for any one of these years is indistinguishable from that for either of the other two years.3. The mean lunar-day rhythm consists of two maxima, of equal magnitude, occurring approximately at lunar zenith and at lunar nadir; between the maxima are two minima symmetrical with respect to time of occurrence and magnitude.4. For the primary lunar rhythm the ratio of maximum to minimum is about 1.4; for the diurnal rhythm the ratio of maximum to minimum is 1.2 in 1955, 1.4 in 1956, and 1.2 in 1957.5. Because of the amplitude of the lunar component of the rhythm, the data for single days reveal clearly the progression of lunar maxima and minima.6. Because of the equality in amplitude of fluctuations correlated in time with lunar zenith and wit...

SEASONAL VARIATIONS IN O2-CONSUMPTION OF UCA PUGNAX

1. Records of the O2-consumption of Uca pugnax were obtained during the summer, autumn, and winter months and analyzed for diurnal and lunar-day rhythms.2. An apparent annual rhythm in mean rate of respiration is reported.3. The respiratory rate during December, January, and February was found to be approximately 50% of that during June, July, and August. During September October, and November, a gradual decrease in rate was observed.4. The form of the diurnal rhythm of respiratory rate showed no changes associated with time of year. Similarly, no seasonal changes in phase relations were observed.5. The range of both diurnal and lunar-day rhythms showed fluctuations but these were not clearly associated with time of year.6. The lunar-day rhythm was found to show changes as follows : June through September the curve was bimodal with maxima at lunar zenith and nadir; beginning in October and continuing through January the curve was unimodal with a maximum near lunar zenith; in February the curve was bimodal...

LAG-LEAD CORRELATIONS OF BAROMETRIC PRESSURE AND BIOLOGICAL ACTIVITY

1. Eight species of living things, ranging from lower to higher plants and lower to higher animals, in studies over a three-year period and including approximately 850 species-days have exhibited without exception a statistically significant leadcorrelation on barometric pressure with an over-all mean coefficient of about 0.5.2. The correlation involved sometimes only the 5-6-7 A.M., sometimes only the 5-6-7 P.M., and other times the mean daily rates of O2-consumption.3. The sign of the correlation was sometimes positive and other times negative. Sign changes, when they occurred during a single period of study were abrupt, and correlated with a 180°-shift in the phase relationships of the concurrent mean solar-day cycles.4. In twelve periods of study, ranging from one to four months each, the correlation in nine cases centered on day n + 2 of barometric pressure. In two cases it centered on day n + 1 and in one, on day n + 7.

SIMILARITIES BETWEEN DAILY FLUCTUATIONS IN BACKGROUND RADIATION AND O2-CONSUMPTION IN THE LIVING ORGANISM

1. O2-consumption of potatoes was recorded continuously through the fourmonth period, February-May, 1956.2. There were daily fluctuations in rate which, even using 3 x 7-hour moving means, displayed a mean amplitude of about 14%.3. Five independent respirometer-recording systems yielded mean daily cycles for the four-month period ranging in amplitude from 4.8 to 10.0% with a mean of 8.2%.4. The mean cycles were of two forms, one essentially 180° out of phase with the other.5. Solar-day and lunar-day mean fluctuations in background radiation were also determined for the period of the investigation.6. A small but very highly significant correlation existed between the fluctuations in amplitude of the daily cycles in radiation on day n-1 and amplitude of the daily fluctuations in O2-consumption in the potato on day n.