Systema Naturae. 1735. Facsimile of the first edition with an introduction and a first English translation of the "Observatio- nes" by M.S.J.Engel-Ledeboer and H.Engel. 1964. (Dutch Classics in Hi- story of Science, 8). 1 portrait. 30. p. -With introduction and a first English translation of the 'Observationes' by M. S. J. Engel -Ledeboer and H. Engel. 1964.- Imitation vellum boards.