Main characteristics of Platyhelminthes:

(i) Their body is bilaterally symmetrical.

(ii) They are triploblastic animals i.e. their tissues differentiate from three embryonic germ layers.

(iii) Excretory system consists of blind tubules called protonephridia, which bear a tuft of cilia at the end called a flame cell.

(iv) They are hermaphrodites i.e. both male and female reproductive organs occur in the same individual.

Examples: Liver fluke (Fasciola) and blood fluke (Schistosoma).