| 21. | The most numerous group is the ascidians; fewer than 100 species of these are found at depths greater than.
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| 22. | Ascidians are found all over the world, usually in shallow water with substratum, such as rocks and shells.
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| 23. | However, most solitary ascidians that are encountered are so covered in algae that the coloration is often not visible.
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| 24. | Vanabins are found almost exclusively in the blood cells, or vanadocytes of some ascidians and tunicates ( sea squirts ).
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| 25. | It is an ascidian, a member of a group of animals called tunicates that includes things like sea squirts _ resembling anemones.
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| 26. | Ascidians are almost all hermaphrodites and each has a single ovary and testis, either near the gut or on the body wall.
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| 27. | But one group, the molgulid ascidians, have evolved tailless species on at least four separate occasions, and even direct development.
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| 28. | These derivatives may either result from a " P . areolatus " symbiont or may come from feeding on the ascidian.
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| 29. | Water is drawn into the ascidian through the buccal ( oral ) siphon and leaves the atrium through the atrial siphon ( cloacal ).
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| 30. | Exceptions to this rule are the sperm chemoattractants of corals, ascidians, plants such as ferns, and algae ( Table 1 ).
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