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The Sand Worms (Phylum Gnathostomula) (514 words) |
 | Gnathostomulids are hermaphroditic with only a single ovary. |
| The eggs leave the body by bursting out through the adults body wall, healing of the adult is quick and there is no larval stage, the egg hatching directly into a small but adult gnathostomulid. |
| Individuals go through one or more feeding but non-reproductive stages followed by a non-feeding but reproductive stage in their lives, and in some species at least it may take a year to complete a life cycle. |
| Phylum Gastrotricha (2789 words) |
| Gnathostomulids are apparently unselective about where or whom they inject with sperm- since it may be found in the wrong body regions and organs and sterile phase individuals are just as likely to be inseminated as sexually mature ones. |
| Fertilization is internal, some males use hypodermic insemination, others, like gnathostomulids, have penes that are adhesive and attach to the body wall of a female-which may drag the male around for some time. |
| The Lansing effect has been found in rotifers (King, 1983), that is that the offspring of old parents tend to have shorter lifespans than the offspring of younger rotifers. |
Feeds |
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