Please read Alexey Sklyarenko's annotations on Pale Fire, Ada and other Nabokov works here.
Before the family dinner in “Ardis the Second” Ada (the title character of a novel, 1969, by VN) mentions “the snake of rhyme” (a play on Van’s words “for the sake of rhyme”):
The neat interplay of harmonious motions, the candid gayety of family reunions, the never-entangling marionette strings — all this is easier described than imagined.
Describing the torments of poor mad Aqua (the twin sister of Van’s, Ada’s and Lucette’s mother Marina), Van Veen (the narrator and main character in VN’s novel Ada, 1969) mentions the Virgin and Venus and calls electricity (banned on Antiterra after the L disaster) “the unmentionable magnetic power:”
Describing the torments of poor mad Aqua (the twin sister of Van’s, Ada’s and Lucette’s mother Marina), Van Veen (the narrator and main character in VN’s novel Ada, 1969) says that Aqua saw flying sharks with lateral eyes taking barely one night to carry pilgrims through black ether across an entire continent from dark to shining sea:
Describing his performance in variety shows as Mascodagama, Van Veen (the narrator and main character in VN’s novel Ada, 1969) mentions the Golden Curtain that separates Tartary (a country that on Demonia, aka Antiterra, Earth’s twin planet on which Ada is set, occupies the territory of the Soviet Russia) from the rest of the world:
When Oks (Osip Lvovich Oksman) shows to Vadim Vadimovich (the narrator and main character in VN’s novel Look at the Harlequins!, 1974) his lending library, Vadim recognizes – among the people who have a business meeting there – his friend Morozov and Boyarski (a sycophant of the critic Basilevski):
Describing his life in Paris, Vadim Vadimovich (the narrator and main character in VN’s novel Look at the Harlequins!, 1974) mentions Adam Atropovich, the unforgettable leader of the talented, illiterate, intuitive new critics:
Describing his meeting with Lucette (Van’s and Ada’s half-sister) in Paris, Van Veen (the narrator and main character in VN’s novel Ada, 1969) mentions the aureate backcloth of a sakarama screen:
Describing the family dinner in “Ardis the Second,” Van Veen (the narrator and main character in VN’s novel Ada, 1969) mentions the cannibal joy of young gourmets tearing ‘plump and live’ oysters out of their ‘cloisters’ in an unfinished canto of Eugene Onegin:
According to Ada, her husband called Demon Veen (in VN’s novel Ada, 1969, Van’s and Ada’s father, the son of Dedalus Veen) Dementiy Labirintovich:
‘My upper-lip space feels indecently naked.’ (He had shaved his mustache off with howls of pain in her presence). ‘And I cannot keep sucking in my belly all the time.’
At the dinner in Bellevue Hotel in Mont Roux Dorothy Vinelander (in VN’s novel Ada, 1969, Ada's sister-in-law) mentions dear Aunt Beloskunski-Belokonski, a delightful old spinster (“a vulgar old skunk,” according to Ada), who lives in a villa above Valvey:
It went on and on like that for more than an hour and Van’s clenched jaws began to ache. Finally, Ada got up, and Dorothy followed suit but continued to speak standing: