ISSN:
1573-5117
Keywords:
Rhabdocoela
;
Platyhelminthes
;
germanium
;
ovary
;
oocyte
;
cortical inclusions
;
ultrastructure
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Ultrastructure features of the germanium (ovary) have been investigated in several species of Rhabdocoela. The gonad is usually unpaired, small and pear-shaped; it is enveloped by an extracellular lamina and contains oocytes at different stages of maturation. Elongate accessory cells surround germ cells in the peripheral zone of the gonad and can also fill the internal spaces between oocytes with their long, flattened processes. The main features observed during oocyte maturation were the appearance of chromatoid bodies, annulate lamellae, lipid droplets and glycogen particles, and the development of R.E.R. and Golgi complexes which appeared correlated with the production of small inclusions that became localized in the cortical ooplasm of mature germ cells. The inclusions exhibited a different structure in different taxa and contained variable amounts of polyphenols. Cortical inclusions of rhabdocoels most probably represent residual shell-granules and may participate in the capsule-shell formation.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00036388
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