Solution: The word CAT can be added to the beginning of twelve symmetrical across entries- 1A, 9A, 14A, 20A, 32A, 35A, 44A, 47A, 59A, 68A, 70A, 72A. The first letters of the clues for these words, in order, spell TWEETY CHASER and we all know that is SYLVESTER.