The stomatopoda are  group of crustaceans called mantis shrimp although they are distinct from shrimp and named mantis for their shared appearance with terrestrial mantids.  They are predatory animals which often ambush from burrow or, less often, actively track and hunt prey.  Prey capture uses very fast moving front appendages typically shaped into a barbed spear or a blunt club, the latter of which can create shock waves similar in nature to those produced by snapping shrimp.  This chart shows the external (1) and internal (2) features of an adult.  The colours represent different systems including the circulartory (red), reproductive (green) and digestive (yellow).  Larval stages are also shown (5-7) which may remain pelagic for up to three months.