. Fresh-water biology. Freshwater biology. Fig. 73. Stephanodiscus niasareoe Ehrenberg. X 606. (Original.) A B 9 (i, 10) Valves more or less cylindrical, often in chains, ends greatly ex- tended, usually forming long spines. Family RmzosoLENlACEAE. Only one genus Rhizosolenia Ehrenberg. Fig. 74. Rhizosolenia eriensis H. Smith. Schroter.) X 190. (After 10 (i, 9) Valves not circular or cylindrical, of different shapes, symmetrical in reference to a longitudinal or transverse axis; surface marked by costae or ptmctate lines making definite angles with a middle raphe or a median Une 11 11(34,38) A
. Fresh-water biology. Freshwater biology. Fig. 73. Stephanodiscus niasareoe Ehrenberg. X 606. (Original.) A B 9 (i, 10) Valves more or less cylindrical, often in chains, ends greatly ex- tended, usually forming long spines. Family RmzosoLENlACEAE. Only one genus Rhizosolenia Ehrenberg. Fig. 74. Rhizosolenia eriensis H. Smith. Schroter.) X 190. (After 10 (i, 9) Valves not circular or cylindrical, of different shapes, symmetrical in reference to a longitudinal or transverse axis; surface marked by costae or ptmctate lines making definite angles with a middle raphe or a median Une 11 11(34,38) A middle nodule present on the raphe of both valves. ... 12 See also 40 and 65. 12 (32, 36) Girdle view symmetrical with reference to both a transverse and a longitudinal axis 13 13 (26) Valves not arched or keeled; usually symmetrical with reference to a straight or a sigmoid raphe. Family Naviculaceae . 14 Valves symmetrical with reference to a straight or curved middle line; girdle symmetrical with reference to both axes; a straight or curved raphe; a central and two end nodules present. 14 (is) Cells without inner partitions; raphe and valves straight. ... 16 15(14) Raphe and valves sigmoid Pleurosigma W. Sm\\ Fig. 75. Fleurosigma attenuatum W. Smith. X 300. (After Smith.) 16 (19) Cells linear, oblong, with rounded nodules, the two end ones turned toward one side, the prominent costae not 17 17 (18) The costae interrupted by a plain band at the center. Stauroptera Ehrenberg. 18 (17) The costae not interrupted at the Pinnularia Ehrenberg. Fig. 76. Pinnularia viridis Smith. X 600. (Original.) 19 (16) Cells more lance-shaped, the end nodules not turned toward one side. Striations composed of lines of individual dots. 20. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Ward, Henry Baldw
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfreshwa, bookyear1918
