Scioto River Forms of Chrysococcus

The genus Chrysococcus comprises some of the most beautiful of the small flagellates. Despite their small size recognition is easy because they are slow moving, frequently motionless for a long time; because they are practically unharmed by formalin preservation; because their brown color is very pronounced; and because specific characters are based on their resistant shells. They occur in abundance in the Scioto River of Ohio, as well as the Tennessee and Ohio Rivers, but are either scarce elsewhere or have been overlooked or neglected by workers with plankton, for there seems to be no reference to the genus in the writings of American workers. Pascherl describes five species, and Fritsch2 cites the occurence of C. rufescens and C. tesselatus in England. Only two of the species described by Pascher, C. rufescens and C. punctiformis, have been noted in the material herewith studied. There is some doubt as to the identification of C. punctiformis, for the organisms while abundant in a few preserved samples, were deep brown in color, which with their small size, 2 to 3 microns, rendered identification questionable, especially as their flagel'la were quite short. C. rufescens has at times occurred in large numbers in the Scioto and some of its tributaries as shown by Fig. 1. To