enlarged around spore. Type species, _Clostridium butyricum_ Prazmowski. As compared with Migula’s classification it is to be noted that there are 38 genera listed by the Committee instead of 13 in the same general groups. The following list of _Genera conservanda_ submitted by the Committee was formally adopted by the Society and these are therefore its official names for the organisms included in these genera. _Acetobacter_ Fuhrman _Actinomyces_ Harz _Bacillus_ Cohn _Bacterium_ Ehrenberg _Chromobacterium_ Bergonzini _Clostridium_ Prazmowski _Erythrobacillus_ Fortineau _Leptotrichia_ Trevisan _Leuconostoc_ Van Tieghem _Micrococcus_ Cohn _Rhizobium_ Frank _Sarcina_ Goodsir _Spirillum_ Ehrenberg _Staphylococcus_ Rosenbach _Streptococcus_ Rosenbach _Vibrio_ Müller _It is greatly to be desired that the Society’s Classification when finally completed shall become the standard in the United States at least._ _Such names as have been adopted by the Society are used throughout this work._ The Committee also submitted the following artificial key for determining the genera in the two orders _ACTINOMYCETALES AND EUBACTERIALES_: A--Typically filamentous forms _Actinomycetacae_ B--Mycelium and conidia formed _Actinomyces_ BB--No true mycelium C--Cells show branching D--Gram negative _Actinobacillus_ DD--Gram positive _Erysipelothrix_ CC--Cells never branch. Gram positive threads later fragmenting into rods _Leptotrichia_ AA--Typically unicellular forms (though chains of cells may occur) B--Cells spherical--_COCCACEÆ_ C--Parasitic forms (except Leuconostoc), cells generally grouped in pairs or chains, never in packets, generally active fermenters. D--Cells in flattened coffee-bean-like pairs, gram -. _Neisseria_ DD--Not as D E--Saprophytes in zoögloea masses in sugar solutions. _Leuconostoc_ EE--Not as E. Gram +. F--Cells in lanceolate pairs or in chains. Growth on media not abundant. G--Cells in lanceolate pairs. Inulin generally fermented. _Diplococcus_ GG--Cells in chains. Inulin not generally fermented. _Streptococcus_ FF--Cells in irregular groups. Growth in media fairly vigorous. White or orange pigment. _Staphylococcus_ CC--Saprophytic forms. Cells in irregular groups or packets, not in chains. Fermentative powers low.