1. Studies have been made of carbohydrate metabolism in Fasciola gigantica during starvation and these are compared with data available about carbohydrate metabolism in F. hepatica.
2. In F. gigantica the glycogen content before starvation was 5·4% of f.w. or 25·35% of D.W. of tissue, and the glycogen content after starvation was 3·5% of F.W. or 16·29% of D.W. of tissue.
3. The medium in which F. gigantica was incubated was analysed for lactic acid as one of the end products of glycogen consumption. The lactic acid given out in a period of 2 hr. was 0·46% of F.W. or 2·18% of D.W. of tissue.
I wish to thank Professor K. Sahai for his generous help in the preparation of this manuscript.