1904 28, 18, 20, 4, 21, 23, 20, 22 p., 5 pls, disbound (no covers). Published in: Archiv für Entwickelungsmechanik der Organismen.Added are four other papers on the Frog's embryology: Sampson, Contribution to Embryology Hylodes martinicensis (2 p., 17 figs, 1 plate - another plate missing) / Todd, Results Injuries to the Blastopore Region of the Frog's Embryo (18 p., 20 figs, 2 pls) / Reed, Formation of the Interior Cells in the Fragmentation of the Frog's Egg (4 p., 4 figs) / King, Experimental Studies on the Eye of the Frog's Embryo (23 p., plate is missing).