The genus Oochoristica Liihe 1898 contains some forty-five valid species of tapeworms parasitic as adults in reptiles and mammals. The extensive literature on the group contains no recent satisfactory summary consequently the amateur collector finds it difficult to classify specimens or to determine them as new. This condition was obvious when the writer recently had occasion to help his students with their descriptions (Peery 1939 and Steelman 1939a and 1939b) of some new species of the genus. In order to remedy this situation the present compendium was prepared and is herewith offered as an introduction to the group.