THE USE OF DATA SHEETS IS ENCOURAGED IN THE UNITS ON CLASSIFICATION. EACH STUDENT IS INSTRUCTED TO CLASSIFY TYPES OF LEAVES ACCORDING TO THEIR SIMILARITIES AND DISSIMILARITIES, AND THEN TO EXCHANGE LEAVES WITH ANOTHER STUDENT IN ORDER TO NOTICE IF INFORMATION ON A NEW SET OF LEAVES WOULD FIT ON THE SAME DATA SHEET. PLANTS ARE NEXT TO BE CLASSIFIED ACCORDING TO THEIR STRUCTURE. DETERMINATIONS ARE TO BE MADE AS TO WHETHER STRUCTURE AS A CLASSIFICATION BASIS IS MORE USEFUL THAN CLASSIFICATION BY LIFE PROCESSES AND ENVIRONMENT. A SPECIAL KEY IS TO BE DEVISED FOR PLANTS, FOLLOWING THE EXAMPLE OF THE KEY INCLUDED IN THE GUIDE FOR ANIMALS. AFTER SETTING UP THEIR OWN SYSTEMS OF CLASSIFICATION, STUDENTS ARE REQUESTED TO RESEARCH TO DETERMINE THE METHODS OF CLASSIFICATION USED BY ZOOLOGISTS. RESEARCH FINDINGS SHOULD BE PRESENTED IN ACCEPTABLE FORM. SELF-EXPRESSION IS ENCOURAGED ON STUDENT EVALUATION OF THE LINNAEUS CLASSIFICATION. THEIR OPINION IS SOUGHT AS TO WHETHER AN UP-TO-DATE KEY WOULD BENEFIT WORKING BIOLOGISTS TODAY.