. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. f Figure 2. Development of Phyllacanthus parvispinus. xylene cleared whole mounts, a. Approximately 30-cell embryo ( h). Note size differences in blastomeres. b. Wrinkled blastula (10 h). The surface is maximally wrinkled at this stage, c. Lobate blastula ( h). Only a few wrinkles remain at this stage, d. Gastrula ( h). The blastopore is quite wide. e. Early larva (45 h). Podial buds are present (arrows), f. Late larva (69 h). The live primary podia surrounding the future adult oral surface are clearly visible, as
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. f Figure 2. Development of Phyllacanthus parvispinus. xylene cleared whole mounts, a. Approximately 30-cell embryo ( h). Note size differences in blastomeres. b. Wrinkled blastula (10 h). The surface is maximally wrinkled at this stage, c. Lobate blastula ( h). Only a few wrinkles remain at this stage, d. Gastrula ( h). The blastopore is quite wide. e. Early larva (45 h). Podial buds are present (arrows), f. Late larva (69 h). The live primary podia surrounding the future adult oral surface are clearly visible, as is a pit opening (arrow). Embryos in panels d-f are oriented animal end up. Formalin-fixed embryos were cleared in xylene before micrography. A, archenteron. Scale bar = 100 j/m. teristic flared ends, and on the fact that they are the first spines to appear. However, these spines differ from the juvenile spines of planktotrophic cidaroids in their clus- ter arrangement on the test and in the fine structure of the lateral processes (Emlet, 1988). Pedicellaria are not yet present, and a large lobe, corresponding to the animal end of the larva, protrudes from one side. During the next few days, metamorphosis is gradually completed: the larval animal lobe is resorbed, circumoral spines de- velop the characteristic lateral processes and flared ends of echinoid juvenile spines, and additional spines appear. By 141 h. the surface is covered by juvenile spines, and five apical test plates are evident (Fig. 4). At this point, test diameter is approximately 500 /urn. Although juveniles at six days of development contain nascent adult test plates, there is no evidence of calcifi- cation in the adult oral field. It is not known when juve- niles begin to feed, but development of the lantern and. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resem
Size: 1247px × 2005px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
