XXÜ
HELEN A. STAFFORD
2. E. O. Dodson, "A Textbook of Evolution." Saunders, Philadelphia, Pennsylvania, 1952.
3. G. G. Simpson, "The Major Features of Evolution." Columbia Univ. Press, New
York, 1953.
4. G. L. Stebbins, Jr., "Variation and Evolution in Plants." Columbia Univ. Press,
New York, 1950.
5. L. Hyman, "The Invertebrates," Vols. I-IV. McGraw-Hill, New York, 19401956.
6. G. M. Smith, "Cryptogamic Botany," Vols. I and II. McGraw-Hill, New York,
1955.
7. W. S. Spector, ed., "Handbook of Biological Data." Saunders, Philadelphia,
Pennsylvania, 1956.
* Most of the names refer to phyla, except in a few cases where some of the
smaller taxonomic groups are shown. Capitalized names written across lines are
groups including all forms above the name.
HELEN A. STAFFORD
2. E. O. Dodson, "A Textbook of Evolution." Saunders, Philadelphia, Pennsylvania, 1952.
3. G. G. Simpson, "The Major Features of Evolution." Columbia Univ. Press, New
York, 1953.
4. G. L. Stebbins, Jr., "Variation and Evolution in Plants." Columbia Univ. Press,
New York, 1950.
5. L. Hyman, "The Invertebrates," Vols. I-IV. McGraw-Hill, New York, 19401956.
6. G. M. Smith, "Cryptogamic Botany," Vols. I and II. McGraw-Hill, New York,
1955.
7. W. S. Spector, ed., "Handbook of Biological Data." Saunders, Philadelphia,
Pennsylvania, 1956.
* Most of the names refer to phyla, except in a few cases where some of the
smaller taxonomic groups are shown. Capitalized names written across lines are
groups including all forms above the name.