| The initial studies involved little flatworms called planaria that have a very primitive nervous system. |
|
| Thus, the list of species studied in his laboratory ranges from planaria to mammals. |
|
| Because planaria tend to stay in or return to darker areas, an increase in light intensity causes an increase in their turning responses. |
|
| The flatworms known as planaria have long amazed scientists with their capacity for regeneration. |
|
| The triclads Dugesia, Polycelis and Planaria have been encountered though Minckley mentions the avoidance of Dugesia in carbonate-depositing areas. |
|
