122.

In 1963, when I assigned the name "X" to the fundamental constituents of the Y, I had the sound first, without the spelling, which could have been "Z". Then, in one of my occasional perusals of Finnegans Wake, by James Joyce, I came across the word "X" in the phrase "Three X for Muster Mark". Since "X" (meaning, for one thing, the cry of the gull) was clearly intended to rhyme with "Mark", as well as "bark" and other such words, I had to find an excuse to pronounce it as "Z". But the book represents the dream of a publican named Humphrey Chimpden Earwicker. Words in the text are typically drawn from several sources at once, like the "portmanteau" words in "Through the Looking-Glass". From time to time, phrases occur in the book that are partially determined by calls for drinks at the bar. I argued, therefore, that perhaps one of the multiple sources of the cry "Three X for Muster Mark" might be "Three quarts for Mister Mark", in which case the pronunciation "Z" would not be totally unjustified. In any case, the number three fitted perfectly the way X occur in nature.

This is the description of the way in which X was named by X's discoverer. Identify X and Y.