Abstract
1. Histochemical and biochemical studies have demonstrated the presence and distribution of phosphatases in Cysticercus tenuicollis and adult Moniezia expansa.2. Biochemical tests have differentiated the following types of optimum phosphatase activity: Cysticercus tenuicollis, acid phosphatase, pH 5·0 (approx.); alkaline phosphatase, pH 10·0 (approx.); Moniezia expansa, acid plaosphatase, pH 5·5 (approx.); alkaline phosphatase, pH 7·0–8·0 and pH 10·0–11·0.3. Attempts to locate the enzymes by normal histochemical methods were unsuccessful in the case of Cysticercus tenuicollis. In adult Moniezia, acid and alkaline phosphatase (both types) occurred in the cuticle. Alkaline phosphatase (pH 10·0–11·0) only was present in the tunicae enclosing the ovary, vitelline gland and testes. This enzyme was also the only one present in the interproglottidal glands, in the wall of the developing uterus and in the subcuticular cells.4. Tests for all types of phosphatase activity showed that cuticular activity in Moniezia originated in the walls of an extensive branched system of channels. This system was demonstrable in the cuticle of fixed and unfixed material.5. Incubation experiments with entire living Moniezia showed that substrates external to the body were capable of being broken down. Similar tests with Cysticercus tenuicollis showed that at least some of the alkaline phosphatase activity recorded by the biochemical tests was located in the cuticle.