1.1. Phosphorylative glycolysis has been demonstrated in cell-free extracts of hydatid cyst scolices. An appropriate phosphate pool appears to be necessary for optimal in vitro activity.2.2. Hydatid cyst scolices contain four hexokinases catalyzing specifically the phosphorylation of glucose, fructose, mannose and glucosamine. 2-deoxyglucose is not phosphorylated by crude or purified preparations. The four hexoses are phosphorylated in position 6. Gluco-, fructo-, and mannokinase activities are inhibited by glucose-6-phosphate, while mannose-6-phosphate inhibits only gluco- and manno-kinases. ADP inhibits competitively fructose phosphorylation by fructokinase. Glucokinase is sensitive to PCMB, the inhibition being partially reversed by cysteine.3.3. Cell-free preparations of hydatid cyst scolices contain in addition to various phosphatases, myokinase, phosphoglucomutase, phosphoglucose, and phosphomannose isomerases, phosphofructokinase, aldolase, glycerophosphate dehydrogenase, and lactic dehydrogenase. The extracts could also catalyze mutation of fructose-1-phosphate to fructose-6-phosphate and isomerization of glucosamine-6-phosphate to glucose-6-phosphate.