Typical flip front wooden case with 12 trays of 12 standard slides, containing a good and clean collection of diatoms including several trays of diatom slides by B. Hartley, other preparers include E.C.P. Bone, H.G. Barber, selected diatoms with lists by NBS, test diatoms by Ernst Leitz Wetzlar, arranged diatoms by K.D. Kemp and an exhibition slide for 125th Aniversary of P.M.S. along with others,