Nina Demurova wrote about the translation Nabokov did, in a book titled Nabokov at Cornell: Subjectivity and Recognition in Feminist Politics, (2003) edited by Gavriel Shapiro. Demurova's chapter is titled "Vladimir Nabokov translator of Lewis Carroll." Her discussion of some difficulties Nabokov faced caught my attention. There is no Russian equivalent for the phrase: Cheshire Cat. If you retranslate it back into English, Nabokov's solution reads, to the question Alice asks, "why is your cat grinning so": "because it's a shrovetide cat, that's why." So reads Ania v strane chudes (1923).
The Lewis Carroll Society of North America in their Winter 2004 newsletter, provides some light on what a "Shrovetide" cat is.
[T]he Cheshire Cat .... was merely replaced by his possible Russian brother, ... a "Shrovetide Cat." It plays upon the Russian proverb... ("not every day is Shrovetide for a cat") . If we try to retranslate this character back into English, he might be called a "Sunday Cat," a cat for whom "every day is Sunday."
Of course, in Russia, in 1923, it wasn't Shrovetide for much.