The notion of monadic Tarski algebra was introduced by A. Monteiro and L. Iturrioz [Revista Un. Mat. Argentina 5, 361 (1962)]. Recently, A. V. Figallo [Algebra Univers. 35, No. 1, 141-150 (1996; Zbl 0833.03020)] determined the free monadic Tarski algebra \(\text{FMT} (n)\) over a finite set of \(n\) free generators. The authors indicate a much easier way of calculating the number of elements of \(\text{FMT} (n)\).