. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Execution Rock. Quadrat Coordinates Figure 4. Small-scale abundance patterns of Molgula pacifica at four sites. with respect to established individuals (Young, 1982; Young and Braithwaite, 1980). None of the correlation coefficients were significant (P. haustor: r = ; C. production: r = ; : r = ; P > for all three). Reproduction and development Unlike many ascidians that spawn during the day fol- lowing dark adaptation, Molgula pacifica released ga- metes during periods of darkness. Al
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Execution Rock. Quadrat Coordinates Figure 4. Small-scale abundance patterns of Molgula pacifica at four sites. with respect to established individuals (Young, 1982; Young and Braithwaite, 1980). None of the correlation coefficients were significant (P. haustor: r = ; C. production: r = ; : r = ; P > for all three). Reproduction and development Unlike many ascidians that spawn during the day fol- lowing dark adaptation, Molgula pacifica released ga- metes during periods of darkness. All eight individuals tested spawned, and all released gametes during, not af- ter, the dark adaptation period. Approximately 100-200 eggs were released by each individual. Adults were main- tained in separate dishes during these experiments, yet all embryos were undergoing development when they were discovered in the morning. In dissecting numerous speci- mens we never found embryos being brooded within the atrial chamber. Thus, M. pacifica is an oviparous her- maphrodite capable of self fertilization. The eggs are 180 ^m in diameter, including the follicle cells. At spawning, the egg has a single outer layer of folli- cle cells surrounding the chorion (Fig. 5). The chorion is closely applied to the egg plasma membrane; thus, the perivitelline space is much smaller than in most typical oviparous ascidians (Fig. 6). Sections of the eggs revealed no test cells (Fig. 5, 6), but careful observation of living material showed a few test cells present (R. Cloney, pers. comra.). Each follicle cell contains a single large vacuole which occupies most of the cell volume. Shortly after spawning, these vacuoles undergo a holocrine secretion of their contents to form the adhesive coat (Fig. 7, 8). This coat, which stains intensely with toluidine blue, swells to occupy a space many times the volume of the original follicle cell (Fig. 9). Those portions of the follicle cell membranes not disrup
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
