560 
seems best to express the production of a body of water in vol- 
ume per cubic meter. I have therefore used this basis through- 
out my paper,and employ it in the following table of compara- 
tive production in some of the representative bodies of water 
thus far reported. 
RELATIVE PLANKTON PRODUCTION BASED UPON MAXIMUM RECORD. 
Depth} Plankton—in cm.' 
Locality Investigator Date —in 
meters | Per sq. ;Per cu. me- 
meter ter, 
Illinois River.......... Kofoid 3, V, 1898) 5.8 413.89] 71.36 
Spoon River .......... “ 11, IX, 1897] 4.12 60.11 14.59 
Quiver Lake.......... es 3, _V, 1898] 4.2 353-98} 84.28 
Dogfish Lake.......... “ 17, IV, 1895} 2.51 102.16] 40.70 rt 
PlagLakens-ue seuss ss 2 V, 1896] 1.64 | 667.55] 407.04 
Thompson’s Lake..... s Dye eV LSOS| (makes 184.32 122.88 | 
Phelps Lake.......... es 23, VIII, 1898 ie 89.79! 448.96 
, 12, VIII, 1896} 1.5 |1439.5*| 684.* 
Turkey Lake...........|Juday, (’97) 12, VIII, 1896] 6.09 eee 135.5* 
Lake St. Clair..........|Reighard, (’94) 17, IX, 1893] 4.37 74.52 17.05 
Lake Michigan.........)Ward, (’95) 11, VIII, 1894] 107.8 | 176.29 1.64 
Danube, backwaters. . .|Steuer, (’or) ? ~~ V, 1898 3? 36 12. 
Elbe, backwaters...... Schorler, (’99) 20, V, 1898! 3-4 | 438-584) 146. 
GardaiScereean eerie Garbini, (’95) -- 50 62 1.24 
JENS Ve Sano oAbonodac Zacharias, (’96)| 10, VIII, 1895} 4o 862 21.55 
loner Sees. eee Apstein, ('96) 6, IX, 1892) 17 1242 73.07 
Dobersdorfer See...... Apstein, (’96) 4, X, 1891] 19.5 4242] 218.05 
Navern See........... Huitfeldt-Kaas, 
(98) ? 7 520] 74.29 
Sognsvandet See....... Huitfeldt-Kaas, 
(98) 30(?), VI, ? |shallow 240 — 
Waterneverstorfer See.)Lemmermann, 
(98) 1898 | 2 70 35. 
Tac) Reman... -seeen Jung, (’99) 18, VI, 1898 120 Iol.9 0.85 
Vierwaldstatter See. ...|Burckhardt, 
(oob) ? \ ? 150. — 
Neuenburger See...... Fuhrmann, ('00); 27, V, 1899 40 91.3 2.24 
IatzenSeerrrerareenee Amberg, ('00) 14, XI, 1898 5 6.2 1.24 
Stithmer See .......... Seligo, (’oo) 9, VIII, 1898| 23 2340 101.79 
*Reduced to settling method of measurement by multiplying by 5. See Juday (’97). 
{All records for our stations reduced to settling method of measurement by multi- 
plying by 2. See page 256. 
A comparison of this maximum production in these various 
localities, upon the basis either of plankton per square or cubic 
meter, ranks our localities (barring Spoon River) among the 
more fertile regions. If the content per cubic meter be the ba- 
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