Click on the yellow stars to link to the page of each feature.  To follow explorer sequence start with the "Surface" map versus this "Submarine" map.  The blue line on this map shows travel by water starting at the Nautilus in the NW corner -  intersections of blue line with land show underground waterways except portions of the "River of Life" (west of the "Cliff Rift") which do some surfacing into the jungle.  Dashed blue line is dry underground exploration and does not intersect with the underground water way between the "Nautilus" and the "Dream Sphere".  As shown by the blue lines - there are 2 separate underground waterways to the Dream Sphere that do not connect.  The only way to get a Mini-Sub Dolphin into the Lagoon (where you find "INMO Island") is from the artificial underground waterway splitting from the River of Life.  For more info on explorer's routes read the Navigation Schemes page.