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Symsagittifera roscoffensis; several individuals of this acoel "worm". |
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Symsagittifera roscoffensis; single specimen. |
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Symsagittifera roscoffensis; anterior part with statocyst and two eyespots. |
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Symsagittifera roscoffensis; head with statocyst and two orange eyespots. The arrowheads point to the frontal organ (sensing). Note also the multi-ciliated epidermis cells which enable the locomotion of the critter. |
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Symsagittifera roscoffensis; statocyst and two eyespots. |
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Symsagittifera roscoffensis; mid part of the body showing the symbiotic protoplasts of the prasinophyte alga Tetraselmis convolutae. The red spots are rhabdocysts. The four lighter longitudal lines (marked by arrowheads) which represent dorsal and lateral neural bundles. |
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Symsagittifera roscoffensis; rhabdocysts |
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Symsagittifera roscoffensis; sagittocysts in the posterior half of the animal. |
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Symsagittifera roscoffensis; crop of the above image. The arrows point to some of the needle-like sagittocysts, whereas the arrowheads mark one of the several spindle-shaped muscle mantles surrounding the sagittocysts. It might be possible that the area marked by the asterisk is a sagittocyte. |
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Symsagittifera roscoffensis; male reproduction organs. |
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Symsagittifera roscoffensis; the double arrow marks the seminal bursa; the arrowhead points to the bursal nozzle which leads from the seminal bursa to the female genital opening. |
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Symsagittifera roscoffensis; bursal nozzle, detail. |
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Symsagittifera roscoffensis; bi-flagellated sperm cels between algal protoplasts that have ben set free by compression of the animal. l |
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Symsagittifera roscoffensis; habitat in the intertidal zone : residual flows during ebb tides. |
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Symsagittifera roscoffensis; habitat in the intertidal zone : residual flows during ebb tides The gren spots consist of thousands of these "worms". |
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Location: Guisseny, Brittany (France), beach |
Habitat: sand of the intertidal zone |
Date: 11.08.2019 |
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