Amsterdam [Delft], Geologisch Mijnbouwkundig Genootschap, 1934. 4to. xii, 143 pp.; nine plates. Original printed wrappers.

The author's thesis, printed separately from the society's Verhandelingen, with a new title, summary in Dutch, and lose-leaf printed "Stellingen" (propositions). The plates show well-preserved specimens, some of new species described by Sanders. With the small stamp of the Dutch geologist G. A. F. Molengraaff (1860-1942) on the front wrapper and title page. On the front wrapper the hand-written note below the author's printed name: "Mevrouw M. Brongersma Sanders". Margaretha Sanders (1905-1996), "palaeontologist, pioneer geochemist, geobiologist and oceanographer" (see S. Turner & G. C. Cadée Zool. Meded. Leiden, 2005) married the Dutch herpetologist Leo Daniel Brongersma (1907-1994) shortly after publication of her thesis. A very good copy.