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The ultrastructure of the small granular, proteinaceous epidermal cells of some British lumbricids (Annelida) and a reassessment of the identity of the so‐called albumen cells
Author(s) -
Richards K. Sylvia
Publication year - 1975
Publication title -
journal of zoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.915
H-Index - 96
eISSN - 1469-7998
pISSN - 0952-8369
DOI - 10.1111/j.1469-7998.1975.tb02256.x
Subject(s) - biology , ultrastructure , golgi apparatus , endoplasmic reticulum , cell type , electron microscope , reticular connective tissue , anatomy , microbiology and biotechnology , biophysics , cell , biochemistry , physics , optics
The ultrastructure of the small granular, proteinaceous cells of 11 species of lumbricid earthworm is described and no species differences were recorded. The cells are characterized by the presence of membrane‐bound, electron dense granules (0.6–0.7 urn in diameter) arising from polarized Golgi systems in close topographical relationship to the granular endoplasmic reticulum. Variations in electron density of the granules appear to be associated with maturation of the granules. The granules show a finely reticular substructure at high magnification. A less than fully mature stage of this cell type is described. The occurrence of the small granular cell type in the annelids is discussed, as is the possible function of its secretion. The confusions in the lumbricid literature concerning this cell type are discussed, and the much referred to figure of the ‘albumen’ cell type in English texts is shown not to be equivalent to the small granular, proteinaceous type referred to in this and a previous histochemical study.