Scintillating Scotoma. (Migraine Scotoma). A scotoma is a âblind spotâ in front of the vision. The visual phenomenon of scintillating scotoma usually appears like a âtwinkling shadowâ or âzig zag patternâ before the eyes.While every experience is a little different, the most common symptoms are âblack spotâ or âtwinkling blurâ appearing before the eyes.he visual phenomenon of scintillating scotoma usually appears like a âtwinkling shadowâ or âzig zag patternâ before the eyes. While every experience is a little different, the most common symptoms are âblack spotâ or âtwinkling blurâ appearing before the eyes.
Cancel. Spiders live all over the world, including trees, dry areas, wet areas, under ground and in the oceans. Discover the different varieties of spiders on the earth with information from a science teacher in this free video on spider habitats.ancel. Spiders live all over the world, including trees, dry areas, wet areas, under ground and in the oceans. Discover the different varieties of spiders on the earth with information from a science teacher in this free video on spider habitats.
Spiders are air-breathing arthropods that have eight legs and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other orders of organisms. Spiders are found worldwide on every continent except for Antarctica, and have become established in nearly every habitat with the exceptions of air and sea colonization. As of November 2015, at least 45,700 spider species, and 113 families have been recorded by taxonomists.