Summary
The ultrastructure of unfertilized and fertilized egg investments ofPomatoceros triqueter is described. A characteristic feature is the presence of a hitherto unrecorded additional investment layer, inserted between the chorion and the “outer border layer”, which is referred to as the intermediate layer. The fertilization reaction consists of the release of cortical granule material into the perivitelline “space”, and the severing of the microvillous cytosome to “outer border layer” connections, thus allowing an increase in the width of the perivitelline “space”. More ridged corrugations are found on the outer surface of the investments in the fertilized as compared with the unfertilized condition.
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This work was financed by a grant from the Science Research Council.
The authors wish to thank Dr. D. W. F. James and Miss R. Owen, of the School of Engineering Science, University College of North Wales, Bangor, for assistance and the use of the Stereoscan; Messrs. P. C. Lloyd and D. Williams for technical assistance; and Professor B. M. Jones for his critical reading of the manuscript.
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Ap Gwynn, I., Jones, P.C.T. On the egg investments and fertilization reaction inPomatoceros triqueter L.. Z.Zellforsch 113, 388–395 (1971). https://doi.org/10.1007/BF00968546
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DOI: https://doi.org/10.1007/BF00968546