Die gattung rhynchoscolex

Reisinger, Erich

doi:10.1007/bf01247277

Cited by 27 publications

(12 citation statements)

References 6 publications

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“…These electron microscopical findings parallel the conflicting light histological observations about the basement membrane in the Catenulida (e.g. well developed basement membrane in Stenostomum virginianum, see Pullen 1957, and lack of basement membrane in Rynchoscolex, see Reisinger 1924). In all cases studied so far (with the possible exception of Stenostomum virginianum) the intercellular matrix at the base of the epithelium if present -is extremely weakly developed.…”

Section: Body Wallsupporting

confidence: 68%

Morphology of the Turbellaria at the ultrastructural level

Rieger

1981

Hydrobiologia

112

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The paper reviews the following systems: body wall, nervous system, protonephridia, parenchyma, digestive system, reproductive system, and includes a summary of the literature. New information is presented for the catenulid and neoophoran body wall-construction, the kalyptorhynch proboscis, the catenulid and haplopharyngid protonephridial construction, and the prolecithophoran spermatozoon and female germ cell. Examples of new features, as well as examples of how electron microscopy has clarified the relative position of structures and their substructures are given from the subcellular level to the organization of whole organs. Fine structural features linking different turbellarian orders are summarized. They apparently support Karling's (1974) latest assessment of the affinities between the turbellarian orders which is based primarily on light histological data, they add the recognition of a special link between the Macrostomida and Haplopharyngida and they suggest the existence of three main evolutionary lines within the Turbellaria.

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Section: Body Wallsupporting

confidence: 68%

Morphology of the Turbellaria at the ultrastructural level

Rieger

1981

Hydrobiologia

112

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“…There is no indication of an ectodermal infolding or of even transient cilia to reflect Beklemishev's (1969) view of statocyst evolution although this does not in itself rule out an ectodermal origin for the statocyst. Except for the statocyst of Rhynchoscolex, which Reisinger (1924) reports to originate from an epidermal infolding, possibly all turbellarian statocysts develop after the nervous system Anlage has formed and without any connection with the external surface. Despite the absence of cilia, the capsule of the statocyst of C. psammophila could indicate an epithelial origin if it were interpreted as an epithelial basal lamina, but other epithelia of the Acoela lack such a lamina (Ehlers, 1985b).…”

Section: Discussionmentioning

confidence: 99%

“…As far as statocyst development is concerned, the only report tracing the embryonic origin of the statocyst is that of Reisinger (1924) who interprets an introflection of the dorsal epithelium in Rhynchoscolex as the statocyst 'Anlage'. In all other instances, despite Beklemishev's (1969) statement that 'almost all Acoela and several other lower turbellarians have a statocyst sunk in the parenchyma, which has lost its connection with the epidermis', the statocysts do not show epithelial origins and are likely to be derived from a nervous-tissue primordium.…”

mentioning

confidence: 99%

Ultrastructural aspects of nervous-system and statocyst morphogenesis during embryonic development of Convoluta psammophila (Turbellaria, Acoela)

Ferrero

Bedini

1991

Hydrobiologia

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The notion that statocysts originated from an infolding of ectoderm lined by ciliated sensory cells has been challenged with evidence of 'capsule'-limited, non-ciliary statocysts in several independent phyla. Statocysts in turbellarians primitively lack cilia and are embedded within or closely adjoined to the cerebral ganglion; they are likely to be derived from nervous tissue. We investigated the development of the simple statocyst in an acoel turbellarian, a statocyst consisting of three cells. Observations of serial TEM sections of embryos at different stages of development support the hypothesis of an inner (nonepithelial) origin of the statocyst. First, a three-cell complex is delimited by a basal lamina; it then undergoes cavitation by swelling, autophagy, and fluid secretion. The statocyst becomes discernible within the precursor ganglion cells while they still contain yolk inclusions. The two outer (parietal) cells, enclosed together by a lo-nm-thick basal lamina, arrange themselves in an ovoid of about 10 pm diameter and surround the inner statolith-forming cell. The statolith is formed later within vacuoles of the statolith-forming cell.

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“…The only points worthy of note here are that their early development looks similar to polyclads and, although most of them hatch as a juvenile, a so-called Luther's larva has been described for Rhynchoscolex simplex (Reisinger 1924 ). The signifi cance of the existence of this larval stage within Platyhelminthes will be discussed later.…”

Section: Catenulidamentioning

confidence: 93%