Nadus and their corresponding Swaroopams that existed in medieval Kerala are given in the table given below. Fill in the missing columns :
| Nadus | Swaroopams |
| Kolathunadu | Kola Swaroopam |
| Eranad | ............(a)................... |
| ................(b)................. | Perumpadappu Swaroopam |
