For example, sea lettuce, also known as Ulva, generally grows in sheets ... In the entire nervous system, there are only about 20,000 neurons, organized into discrete collections called ganglia. Each ...

Researchers were stunned when they found a sea slug in the Midnight Zone, between 1,013 and 4,009 meters (3,323 to 13,153 feet). The discovery was surprising because no other sea slug had been ...