. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. ESOPHAGEAL EPIDERMIS CIRCUMFERENTIAL] RADIALJ-MUSCLE LAYERS CONNECTIVE TISSUEV^ XV -^ —^ -^ \\. SECRETORY CELL SUPPORTING FIBER 100pm OUTER EPIDERMIS —I 91 tj FIGURE 6. Section of edge of peristomial membrane (lip). The surface of the lip region is covered by thick secretory epithelium with scattered cilia. The lips are retracted by an inner layer of radial muscle fibers and closed by circumferential fibers. in these spines. The lumena are filled with darkly staining nuclei and granules which do not react like secretory mate
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. ESOPHAGEAL EPIDERMIS CIRCUMFERENTIAL] RADIALJ-MUSCLE LAYERS CONNECTIVE TISSUEV^ XV -^ —^ -^ \\. SECRETORY CELL SUPPORTING FIBER 100pm OUTER EPIDERMIS —I 91 tj FIGURE 6. Section of edge of peristomial membrane (lip). The surface of the lip region is covered by thick secretory epithelium with scattered cilia. The lips are retracted by an inner layer of radial muscle fibers and closed by circumferential fibers. in these spines. The lumena are filled with darkly staining nuclei and granules which do not react like secretory material with PAS or toluidine blue. Furthermore, SEM showed the total absence of pores in miliary spine epithelium (Fig. 4C). The large, terminal pores shown by Ghiold (1982) are undoubtedly artefacts due to poor specimen preparation: air-dried material is unsuitable for cellular details, such as microvilli, secretory pores, or cilia. The relatively large holes and depressions along the spine shafts (Figs. 2B, F) correspond with openings in the underlying stereom. The absence of secretory cells or granules within the spines, indicates that these openings, which might be artefacts, are not secretory pores. Sand dollars such as Leodia and Mellita are thought to use the primary and miliary spines as a two-tiered sieve mechanism (Goodbody, 1960; Bell and Frey, 1969; Seilacher, 1979; Lane and Lawrence, 1982) which dislodges diatoms and organic debris from substrate particles. This material is then collected by ciliary currents and perhaps mucus secretion, moved to the mouth along well-defined food grooves, and there ingested. No such mechanism exists in E. pusillus. It is equipped with some of. 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 resemble the original Marine Biological Laboratory (Woods Hole, Mass. ); Marine Biological La
Size: 1488px × 1679px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
