Patella pellucida Patella pellucida Patella pellucida, common name the blue-rayed limpet, is a species of small saltwater limpet, a marine gastropod mollusc in the family Patellidae, the true limpets. This limpet occurs off the eastern Atlantic coasts from Iceland and Norway, to Portugal. It is absent from the Baltic Sea, East Denmark, Belgium and the Netherlands. Up to 15 mm long when fully grown, this species is easily identified by its translucent amber shell with brilliant blue spots running in lines across the top of the shell. The blue-rayed limpet lives primarily on "Laminaria" (kelp) in strong flowing water but also on
Composition of the human body Not all elements which are found in the human body in trace quantities play a role in life. Some of these elements are thought to be simple bystander contaminants without function (examples: caesium, titanium), while many others are thought to be active toxics, depending on amount (cadmium, mercury, radioactives). The possible utility and toxicity of a few elements at levels normally found in the body (aluminium) is debated. Functions have been proposed for trace amounts of cadmium and lead, although these are almost certainly toxic in amounts very much larger than normally found in the body. There is evidence that