|| Separata de An. Aula Dei, Vol. 2, 1951, pp. 187-194. Offprint. First edition. Scarce offprint from Joe Hin Tjio who a few years after this was the first person to recognize the normal number of human chromosomes. Blandy Experimental Farm stamp front cover, some hints of foxing else very good. Tjio's offprints seldom hit the market. * Worldcat shows only one holding in Spain.