Asyndeton
The connection of sentences, phrases or words without any conjunctions is called asyndentic.
Asyndeton helps the author to make each phrase or word sound independent and significant.
Asyndeton generally creates an effect that the enumeration is not completed.
Asyndeton also creates a certain rhythmical arrangement, usually making the narrative measured and energetic.
e.g. She watched them go; she said nothing; it was not to begin then.
Polysyndeton
Polysyndeton is the connection of sentences, phrases or words based on the repetition of conjunctions or prepositions.
The repetition of the conjunction and before each word or phrase stresses these enumerated words or phrases.
Polysyndeton is sometimes used to retard the action and to create the stylistic effect of suspense.
Besides, polysyndeton is one of the means used to create a certain rhythmical effect.
e.g. He put on his coat and found his mug and plate and knife and went outside.