Title: The Biological bulletin
Identifier: biologicalbullet186mari (find matches)
Year: [1] (s)
Authors: Marine Biological Laboratory (Woods Hole, Mass. ); Marine Biological Laboratory (Woods Hole, Mass. ). Annual report 1907/08-1952; Lillie, Frank Rattray, 1870-1947; Moore, Carl Richard, 1892-; Redfield, Alfred Clarence, 1890-1983
Subjects: Biology; Zoology; Biology; Marine Biology
Publisher: Woods Hole, Mass. : Marine Biological Laboratory
Contributing Library: MBLWHOI Library
Digitizing Sponsor: MBLWHOI Library

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LARVAL ASEXUAL REPRODUCTION 69
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Figures 20-21. Scanning electron micrographs of the exterior and interior surfaces of newly released secondary embryos. Figure 20. Scanning electron micrograph of a blastula-stage individual that has been broken open. The epithelium (E) is composed primarily of ciliated columnar cells, but circular holes suggest that at least one other cell type is present. The blastocoelic space is filled with cells: in this micrograph small spherical cells (S) are notable. Scale bar = 28 ^m. Figure 21. Scanning electron micrograph of the basal face of the outer epithelium of a blastula-stage embryo. Present are mesenchyme-like cells (M) and smaller spherical cells (S). The inner surface of the epithelium is lined with a fibrous meshwork. Scale bar = 9 jim. Figures 13-19. Light and scanning electron micrographs that depict the sequence of events during the process of asexual reproduction by budding. Figure 13. Light micrograph showing the rounded appearance of the arm apices (B) and the associated accumulation of cells (*). Scale bar = 58 ^m. Figure 14. Light micrograph of a bud near the time of release from the primary larva. The site of bud/ larva junction is designated by the arrow. Scale bar = 38 ^m. Figure 15. Light micrograph of a released bud in a blastula-like condition. In this individual, the cell- free blastocoel (b) is small and the blastocoelic space contains a large number of cells (*). Scale bar = 33 urn. Figure 16. Light micrograph of a free-swimming secondary embryo undergoing gastrulation. The de- veloping archenteron (closed arrow) is formed by the invagination of the epithelium into the blastocoel (b). Blastopore—BL; scale bar = 25 Mm. Figure 17. A light micrograph showing a fully formed gastrula-stage secondary embryo produced by asexual reproduction by budding. The well-developed archenteron (filled arrow) leads from the blastopore (BL) into the blastocoel (b). The accumulation of cells at the apex of the archenteron (*) is seen in many individuals and may be involved in the formation of the coeloms of the secondary larva. Scale bar = 27 nm. Figure 18. A light micrograph of a dorsal view of a newly formed secondary bipinnaria larva. The ciliated band (arrowhead) has formed and the primordium of the coelomic system of the secondary larva (CO) is clearly evident at the anterior extent of the developing larval gut (filled arrow). Scale bar = 23 >im. Figure 19. Scanning electron micrograph of a fully formed secondary bipinnaria larva that developed from a bud released from a primary larva. Anus—A: mouth—M; ciliated band—(filled arrow): scale bar

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