. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Figure 2. A freshly cut tunic slice (A) and a rounding tunic specimen after incubation in FSW for 24 h (B). Arrowhead indicates a zooid frag- ment extruded from the tunic ball. Magnifications of these two figure parts are the same. Scale bar = 1 mm. Results Freshly cut tunic slices were basically thin rectangular pieces of tunic (Fig. 2A), and each of them rounded up into an elastic tunic ball after incubation in ASW (Fig. 2B). The tunic ball was completely filled with tunic matrix, and no hollows remained. During the incuba
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Figure 2. A freshly cut tunic slice (A) and a rounding tunic specimen after incubation in FSW for 24 h (B). Arrowhead indicates a zooid frag- ment extruded from the tunic ball. Magnifications of these two figure parts are the same. Scale bar = 1 mm. Results Freshly cut tunic slices were basically thin rectangular pieces of tunic (Fig. 2A), and each of them rounded up into an elastic tunic ball after incubation in ASW (Fig. 2B). The tunic ball was completely filled with tunic matrix, and no hollows remained. During the incubation, some of the zooid fragments were pushed out from the rounding tunic specimens, and the others were packed inside the tunic ball, but rounding occurred even if every zooid frag- ment in a tunic slice was lost. Tunic rounding, therefore, did not depend on the presence of zooids or zooid frag- ments. The size of a tunic ball depended on the initial size of the slice and the quantity of zooid fragments that were lost during rounding. For instance, tunic slices of about X 5 X mm transformed to tunic balls of 2 to mm in diameter. In a few cases, one tunic slice would round up into two or three balls connected to each other by thin strands of tunic material, or a tunic slice deformed into a rodlike or irregularly shaped mass of tunic. Within a tunic ball or deformed tunic mass, the tunic cells were alive and some were motile. Noticeable tunic rounding began 4 to 5 h after a slice was prepared, and proceeded gradually for about 20 h; typical time courses are shown in Figure 10 15 20 25 Incubation time (hr) 30 35 Figure 3. Time course of rounding of the tunic slices. The length of the longest diagonal line was measured in three specimens every hour during the incubation in FSW. Table I shows the results of the tunic rounding assay under experimental conditions. In ASW (control), most of the tunic slices became tunic balls; those that did not form balls stuck on the
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
