Nematocyst development was watched in living cells of a siphonophore, Rosacea cymbiformis. The secretion differentiates in the formative cell into an ovoid capsule, continuous with a long apical tube. The entry of this ‘external’ tube into the capsule creates the coiled internal ‘thread’ of the mature nematocyst. Electron microscopy shows that the tip of the external tube inverts and moves down the tube towards the capsule. Complex pleats form during inversion. Thus formation of the internal thread is the geometrical converse of discharge. Extensive repacking of the triply pleated, internal thread occurs, and subsequently the barbs form.
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JOURNAL ARTICLE| 01 September 1973
The Secretion and Development of Nematocysts in a Siphonophore
R. J. SKAER
Department of Medicine, Hills Road, Cambridge, CB2 1QT, England
Received: 12 Feb 1973
Online Issn: 1477-9137
Print Issn: 0021-9533
Copyright © 1971 The Company of Biologists Ltd.
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R. J. SKAER; The Secretion and Development of Nematocysts in a Siphonophore. J Cell Sci 1 September 1973; 13 (2): 371–393. doi: https://doi.org/10.1242/jcs.13.2.371
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