Kansas City, Aug. 23.- Barnet Pruzen, a well-known local commisslon merchant, is at the head of a movement to form a Jewish colony in Porto Rico. "I already have," he said, "the promise of nearly fifty families to join me. These families can raise from $500 to $5,000 each to put into the venture and if all agree we will form a communistic colony. We hope to leave by Jan. 1."