Cladocera of Des Moines and Vicinity

This investigation was begun in April, 1901 and collections were made at various intervals during that spring. During the summer of 1901 eight or nine weeks were spent in collecting and identifying specimens. Again in the summer of 1902 the work was taken up for about five weeks and during the early part of the summer of 1903 further collections were made. At odd times during all this period new specimens have been noted as they were found in material collected for work in the Drake Zoological Laboratories