Deep in the tissues of sea anemones, corals, and jellyfish are strange yellow cells which are genetically distinct from the marine animals. More than a century after these cells were first assigned a now forgotten genus, a new paper has resurrected the name and described six new species from around the world. First described in 1881, the yellow things were originally classified under the genus Zooxanthella by scientist Karl Brandt. Brandt also coined the term zooxanthellae, which is used colloquially to this day. However, another scientist – a Scotsman called Patrick Geddes - was investigating these yellow cells at the...