FEEDING MECHANISMS AND NUTRITION IN THREE SPECIES OF BRESSLAUA

Abstract

1. Three species of Bresslaua, B. vorax Kahl, B. insidiatrix sp. nov. and B. sicaria sp. nov. are described. 2. These ciliates are carnivorous and feed on other small ciliates, members of the genus Colpoda being especially favorable as food. 3. Using indicator dyes it was found that the prey is killed simultaneously with a sudden release of an acid into the newly-formed food vacuole. The hydrogen ion concentration of the vacuole fluid was estimated to be between pH 3.0 and pH 4.2. This range includes the death point of various species of Colpoda. During digestion the protoplasm of the prey becomes alkaline. The undigested residue becomes acid before defecation. 4. Bacteria-free Bresslaua were tested with a number of food organisms and a preliminary survey of their food requirements recorded.