Representatives of the major groups of carbon-containing substances were tested against dextrose as the standard source. In general, the two species of Linderina responded in a similar way and all compounds tested could be utilized at least to some extent.Carbohydrates proved to be utilized best and gave the highest yields, the hexose monosaccharides, disaccharides, and some polysaccharides being rather better than the pentose monosaccharides and the trisaccharide raffinose. Organic acids were not as efficient as the better carbohydrates but gave moderate to good yields whereas the sugar acids and alcohols were much poorer. The single glucoside tested gave the lowest yield.