| Thus, the list of species studied in his laboratory ranges from planaria to mammals. |
| We mentioned that when a piece is cut from a planaria between pharynx and head a new mouth is formed in the middle. |
| This planaria may be cut into several pieces, and each will reproduce what is requisite to complete the mangled organism. |
| Because planaria tend to stay in or return to darker areas, an increase in light intensity causes an increase in their turning responses. |
| It seems also possible that Morgans well-known experiment on regeneration in planaria can be explained by a flow of substances. |
| The initial studies involved little flatworms called planaria that have a very primitive nervous system. |
