Question: What was the Roud Folk Song Index of the nursery rhyme inspiring What Are Little Girls Made Of?

Passages:
"Billy Boy" is a traditional folk song and nursery rhyme found in the United States.  It has a Roud Folk Song Index number of 326.  It is a variant of the traditional English folk song "My Boy Billy", collected by Ralph Vaughan Williams and published by him in 1912 as number 232 in "Novello's School Songs".  The song is very popular with the Orange Order. "Pretty Little Dutch Girl" is a children's nursery rhyme, clapping game and jump-rope rhyme.  It has a Roud Folk Song Index number of 12986. Tweedledum and Tweedledee are fictional characters in an English nursery rhyme and in Lewis Carroll's "Through the Looking-Glass, and What Alice Found There".  Their names may have originally come from an epigram written by poet John Byrom .  The nursery rhyme has a Roud Folk Song Index number of 19800.  The names have since become synonymous in western popular culture slang for any two people who look and act in identical ways, generally in a derogatory context. "Aiken Drum" is a popular Scottish folk song and nursery rhyme, which probably has its origins in a Jacobite song about the Battle of Sheriffmuir (1715).  It has a Roud Folk Song Index number of 2571. "Row, Row, Row Your Boat" is an English language nursery rhyme and a popular children's song.  It can also be an "action" nursery rhyme, whose singers sit opposite one another and "row" forwards and backwards with joined hands.  It has a Roud Folk Song Index number of 19236. "Three Little Kittens" is an English language nursery rhyme, probably with roots in the British folk tradition.  The rhyme as published today however is a sophisticated piece usually attributed to American poet Eliza Lee Cabot Follen (1787–1860).  With the passage of time, the poem has been absorbed into the "Mother Goose" collection.  The rhyme tells of three kittens who first lose, then find and soil, their mittens.  When all is finally set to rights, the kittens receive their mother's approval and some pie.  It has a Roud Folk Song Index number of 16150. "Did You Ever See a Lassie?"  is a folk song, nursery rhyme, and singing game.  It has a Roud Folk Song Index number of 5040. "A Wise Old Owl" is an English language nursery rhyme.  It has a Roud Folk Song Index number of 7734 and in The Oxford Dictionary of Nursery Rhymes, 2nd Ed.  of 1997, as number 394.  The rhyme is an improvement of a traditional nursery rhyme "There was an owl lived in an oak, wisky, wasky, weedle." "What Are Little Boys Made Of?"  is a popular nursery rhyme dating from the early 19th century.  It has a Roud Folk Song Index number of 821. "What Are Little Girls Made Of?"  is episode seven of the of the American science fiction television series, "".  It was first broadcast October 20, 1966, and repeated, two months later, on December 22, the first episode of the series to be repeated on NBC.  It was written by Robert Bloch and directed by James Goldstone.  The title of the episode is taken from the fourth line of the 19th century nursery rhyme, "What Are Little Boys Made Of? ."

Supporting sentences:
 The title of the episode is taken from the fourth line of the 19th century nursery rhyme, "What Are Little Boys Made Of? "What Are Little Boys Made Of?"  It has a Roud Folk Song Index number of 821.