14 the note describes the materials probably while they were at the Society and not at the Farlow Herbarium. The materials described in the note have not been found in the Society's archives, the Farlow Herbarium or the Peabody Museum (as suggested in an appended notation on the note). A small wooden box containing 46 vials bearing numbers and labels corresponding to entries in the 1860 Catalogue was found in the Farlow Herbarium in 1976. It contained an unsigned note indicating These diatoms were collected by [Louis François de] Pourtales and sent to Bailey (J.W.) to name. They were found in the Agassiz Museum [in] October, 1912 and given to [the] Cryptogamic Herbarium [by Samuel Henshaw]. The numbers probably correspond to lists of J.W. Bailey in the Boston Soc. Nat. Hist. In the 1940's David Linder produced a list of the contents of the vials based on data in the 1860 Catalogue. I have made slides from the contents of each of these vials and given each the number of the vial prefixed by a "U", e.g. U231, on a round, 0.8 cm diameter, white label. Lastly, the general slide collection of the Boston Society of Natural History contained 16 slides specifically labelled indicating that they had been prepared from particular vials of unmounted material in the Bailey Collection. Each of these slides has been given the number of the vial from which it was prepared, again, prefixed with a "U" on the characteristic white label. All 64 slides prepared from unmounted material have been placed in Box #20. Many slides were made from Bailey's unmounted material while it was possessed by the Society, especially before 1900, and undoubtedly these were dispersed and now are in different slide collections at the Farlow and other herbaria. Identification of these has not been undertaken now, but when it is done, it will be difficult and largely based on