Morphological variation of axial non-muscular proboscis types in the Polychaeta

Tzetlin, A.; Zhadan, A.

Авторы: Tzetlin A., Zhadan A.
Журнал: Zoosymposia
Том: 2
Год издания: 2009
Издательство: Magnolia Press
Местоположение издательства: New Zealand
Первая страница: 415
Последняя страница: 427
Аннотация: An axial non-muscular proboscis is present in many of the sand- or mud-swallowing species of Arenicolidae, Maldanidae, Capitellidae, Opheliidae, Orbiniidae, and Paraonidae (Tzetlin & Purschke 2005). These proboscides are composed of epithelial, glandular, and sensory cells but the musculature is weakly developed (Purschke 1988; Saulnier-Michel 1992). Arenicolidae, Maldanidae, and Capitellidae have unciliated epithelia, whereas Paraonidae, Orbiniidae, Scalibregmatidae, and Opheliidae bear cilia on the surface of the proboscis. Eversion of the proboscis is achieved by changes in hydrostatic pressure in the anteriormost compartments of the body cavity. The pressure increase is effected by contractions of the musculature of the body wall and is limited to the anterior part of the body cavity by a strong muscular septum (diaphragm or gular membrane). This structure is found in Capitellidae,Arenicolidae, Opheliidae, and Scalibregmatidae(Ashworth 1902; Tampi 1958; Purschke & Tzetlin 1996). The proboscis is withdrawn by the activity of retractor muscles.In this paper we differentiate between the terms “mouth opening” and the opening of the soft axial proboscis (“proboscis opening”). When the proboscis is retracted, the mouth opening is a hollow surrounded by lips that lead to the digestive tract. When the proboscis is everted from the mouth opening, the hollow that leads to the posteriormost parts of the digestive tract (proboscis opening) is located on the top of the axial proboscis.
Добавил в систему: Цетлин Александр Борисович

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Morphological variation of axial non-muscular proboscis types in the Polychaetaстатья

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