See Robert W.L. Kleiner, Chinese Snuff Bottles from the Collection of George and Mary Bloch, Hong Kong, 1987, p. 92, fig. 29, for a Yangzhou seal school bottle depicting a cat watching butterflies where the author states that the word for 'cat' and 'octagenarian', mao, are phonetically close and that the rebus expresses the wish that the recipient should live to be seventy or eighty (butterflies symbolize the numeral seventy).