In the Walrus and the Carpenter sequence, the R in the word "March" on the mother oyster's calendar flashes. This alludes to the old adage about only eating oysters in a month with an R in its name. That is because those months without an R (May, June, July, August) are the summer months in England, when oysters would not keep due to the heat, in the days before refrigeration.
read more facts...