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. Bulletin. Natural history; Natural history. 386 pH selected* Bluegills (Lepomis pallidusj. Wells ('15) 7.7-7.9 Bullhead (Ameiurus melas), Wells ('15) 7.4-7.7 Crappie (Pomoiis annularis). Wells ('15) 7.3-7.4 Rock bass (Ambloplites rupestris), Shelford and Allee ('11) 7.9 Golden shiner (Abramis crysoleucas), Shelford and Allee ('11) 7.7 *pH calculated by Greenfield and Baker equation mentioned on p. 3So.. Lepomis humilis Micropterus salmoides Micropterus dolomieu Ambloplites rupestris Abramis crysoleucas Lepomis megalotis Lepomis cyanellus Pimephales notatus Notropis whipplii Notropis cornutus Fig. 1. Showing the range of hydrogen ion concentrations selected by ten species of flsh (about 12 experiments per species). The actual selections are plotted, and a brolven line indicates the author's impression as to the prol>able range in wliich they would l)e found. The polygons fall approximately in the order of occurrence in swift water. The letters indicate occurrence in creeljs (C). small rivers (S), and in lalies and ponds (Li. When two or three letters are used in connection with a polygon, the first one indicates the type of water in which the species is most numerous, and a single letter signifies that the species is commonly found only in that one type of water. An Examination of certain Illinois Waters with Special Reference to Hydrogen Ion Concentration A study of fish breeding-grounds was conducted by the author in 1919-20, and the pH vaKies observed are shown in Table VI; the oxygen, in Table VII. There was a marked difference between the carp and bass breeding-grounds; in no case were they the same either at the top or bottom. The bass breeding-grounds were characterized by clean sand bottom; the carp grounds, by dark mud. Table VI shows sharp differ- ences in oxygen content at the bottom at all dates on which they were examined.. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - co
