Zoomorphology

, Volume 123, Issue 2, pp 65–80 | Cite as

Ultrastructure and histochemistry of the foregut in Wirenia argentea and Genitoconia rosea (Mollusca, Solenogastres)

Original Article

Abstract

Wirenia argentea and Genitoconia rosea feed on Cnidaria like most representatives of the molluscan taxon Solenogastres (Aplacophora, Neomeniomorpha sensu Scheltema). The structure and histochemistry of the foregut are described based on histologic, semithin, and ultrathin section series. The ultrastructure was analyzed by means of transmission electron microscopy. There are two sets of unicellular glands: a narrow row of preoral gland cells opening to the preoral area, and pharyngeal gland cells in high numbers. Preoral gland cells produce serous secretions in W. argentea, but mucosubstances in G. rosea, whereas pharyngeal gland cells are similar in structure and histochemistry in both species. Based on the size and electron density of gland vesicles, five distinct types of pharyngeal gland cells can be defined. In contrast to earlier assumptions, all types of pharyngeal gland cells produce serous secretions, most probably representing digestive ferments, but no mucosubstances.

Keywords

Foregut glands Pharyngeal glands Feeding Mollusca Aplacophora Neomeniomorpha 

Notes

Acknowledgements

Specimens for this study were collected at Trondheim Biological Station, Norway, with support of the "Training and Mobility—Large Scale Facility programme of the EC". We would like to thank Jon-Arne Sneli (Trondheim) for his helpfulness and the cession of his laboratory for 3 weeks, C. Handl for semithin section series, and Monika Bright and Michael Stachowitsch (Vienna) for revision of the English text and useful suggestions. Financial support was granted by the FWF (Austrian Science Fund), project number P14330-BIO.

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Copyright information

© Springer-Verlag 2003

Authors and Affiliations

  1. 1.Institute of ZoologyUniversity of ViennaViennaAustria

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