Ultrastructural study of metamorphosis in the freshwater bryozoanPlumatella fungosa(Bryozoa, Phylactolaemata)
作者:
TERRY SENSENBAUGHI,
ÅKE FRANZÉN,
期刊:
Invertebrate Reproduction & Development
(Taylor Available online 1998)
卷期:
Volume 34,
issue 2-3
页码: 301-308
ISSN:0792-4259
年代: 1998
DOI:10.1080/07924259.1998.9652664
出版商: Taylor & Francis Group
关键词: Bryozoa;Phylactolaemata;Plumatella;metamorphosis;ultrastructure;phylogeny
数据来源: Taylor
摘要:
At metamorphosis the attachment of thePlumatellalarva to the substrate is effected by secretions from glandular cells in the apical plate, the leading pole during swimming. The larval mantle folds back and slides down towards the substrate. By ciliary activity an adhesive secretion is spread over the metamorphosing larva and the attachment area. Two polypides appear through the larval terminal opening. The mantle fold, together with gland cells, nerve cells, sensory cells, and muscle cells from the larva form a nutritive cell mass. Reduction of this nutritive cell mass is accomplished by autolysis and phagocytosis. An invaginated area of the nutritive cell mass is provided with a dense layer of microvilli, which seem to have an absorbtive function. The nutritive cell mass consisting of transitory larval tissues provides a significant source of nutrient for the developing polypide buds.
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