6 In accounting for the second part of the bequest, Durkee reported that among the approximately 4,500 algae or seaweeds contained in 15 portfolios that "The Diatomaceae are in one volume and amount to 425." Finally, the geographical locations from which samples in the "boxes, paper, vials," etc. in the third part of the bequest were derived imply that they contained diatoms. In summary, the bequest included diatom materials in the partially defined microscopic slide collection, in a clearly segregated portion of the algal collection, and in the poorly defined "rough material for microscopic research." The Society produced in 1860 a Catalogue of the Unmounted Materials [of the] Bailey Collection ..., presumably describing materials in the third part of the bequest. It itemized the collection notes of 705 bottles of materials containing primarily infusoria, but the proportion of the "rough material" that these represent is unknown. In the Annual Report of 1877 the contents of the "Microscopical Collection" were given as 1,838 slides "presented in the bequest of Professor Bailey" (Proc. Boston Soc. nat. Hist. 19:188-189. 1877). However, this report additionally indicated that All the slides of the Bailey Collection, which contained several species of Foraminiferae or Diatomaceae, and which had been identified by Prof. Bailey himself, are entered in a separate book, entitled "The Catalogue of the Bailey Microscopical Slides." These slides are registered under the same numbers as in the current catalogue, but instead of only one line devoted to a general description and name of the locality, the space of half a page or more is devoted to the list of the species found upon that particular slide, together with the marks and measurements for finding each specimen. Prof. Bailey had begun this catalogue by registering 793 slides in this manner on foolscap paper, and this was continued by Miss Washburn. 1391 slides were entered in a similar manner by this lady upon