. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 14 R. H. BREWER One-way ANOVA is used to analyze these data; variances among treatments are homogeneous. The row and column effects for the Latin squares are non-significant ( < P < and < P < , respectively). RESULTS The planulae show no difference (F| 90 = ; < P < ) in their average number of encounters with either plastic ( ± ) or glass coverslips ( ± ) during the control observations. This ratio of contact between plastic and glass () does not change amon
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 14 R. H. BREWER One-way ANOVA is used to analyze these data; variances among treatments are homogeneous. The row and column effects for the Latin squares are non-significant ( < P < and < P < , respectively). RESULTS The planulae show no difference (F| 90 = ; < P < ) in their average number of encounters with either plastic ( ± ) or glass coverslips ( ± ) during the control observations. This ratio of contact between plastic and glass () does not change among the four time intervals during the eight hour observation period (, , , ). The probability of encountering these two substrates when they are simultaneously available to planulae is the same, and the differences in attachment on them in the experiments, below, cannot be attributed to different relative availability of these surfaces to planulae. The response of planulae when encountering glass or plastic is shown in Figure 1. First, planulae on both materials show similar behavior with respect to coverslip surface: they appear to glide on the upper surface (just as they do on the bottom of their container) slowly rotating about their long axis in a clockwise direction when viewed from their aboral (anterior) pole; but on the under surface they become vertically oriented at a particular spot with their aboral end against it where they continue to rotate clockwise. Change of location is preceeded by a brief quickening of rotation and a rapid lateral movement of 1-2 mm while still vertically oriented, followed by a loss of contact and swimming in an arc-shaped trajectory as shown in Figure 1, prior to resuming a position normal to the surface upon renewal of contact. Second, differences in the duration of rotation (seconds; confidence limits) by the vertically oriented planula while against the under surface on glass (; , ) and plastic (; , 1
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
