These names are given to a mutation stop of 1-1/3' pitch. While many sources equate the Larigot with the Nineteenth, properly speaking the former is a flute and the latter a principal. The Larigot originated in 16th-century France; the name comes from l'arigot, a French word denoting a small flute or flageolet. While Williams places it in the Grand Orgue or Positif of the classical French organ, Bedos states that it is only found in the Positif where it is a full compass stop. It could be open or tapered. Bedos names it the highest pitch in the organ, and Douglass reports that it was higher than the highest pitches found in either the Fourniture or Cymbale. The Larigot was introduced to England by Renatus Harris in the 17th century. There are other, more common meanings for the name Flageolet, and another meaning for Petit Nasard.
The most common name by far is Larigot, with 350 examples listed in Osiris, though five are mixtures of II or III ranks, and three are (possibly erroneously) at 2' pitch. Osiris contains 13 examples of Diez y Novena; the earliest ones are listed below. The same source contains one example of Nasath. Of the 150 examples of Flageolet[t] listed in Osiris, only two are at 1-1/3' pitch. About 10% of the examples of Sifflöte and its variants in Osiris are at 1-1/3' pitch. No examples are known of Diezmonovena or Petit Nasard.