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| | ADW: Arthropoda: Information |
 | | Most of the body cavity is an open "hemocoel," or space filled loosely with tissue, sinuses, and blood. |
 | | The circulatory system is open and consists of a heart, arteries, and the open spaces of the hemocoel. |
 | | Respiration takes place through the body surface, and/or by means of gills, tracheae, or book lungs. |
| animaldiversity.ummz.umich.edu /arthropoda.html (560 words) |
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