O. A. JOHANNSEN, Ph.D.
Reading edition
Professor of Biology, Cornell University

ITHACA, NEW YORK
THE COMSTOCK PUBLISHING COMPANY
1915
COPYRIGHT, 1915
BY THE COMSTOCK PUBLISHING COMPANY,
ITHACA, N. Y.
Press of W. F. Humphrey Geneva, N. Y.
Reading edition
Professor of Biology, Cornell University

ITHACA, NEW YORK
THE COMSTOCK PUBLISHING COMPANY
1915
COPYRIGHT, 1915
BY THE COMSTOCK PUBLISHING COMPANY,
ITHACA, N. Y.
Press of W. F. Humphrey Geneva, N. Y.