. Fresh-water biology. Freshwater biology. HYDRA AND OTHER FRESH-WATER HYDROZOA 321 7 (8) Gray, brown, or reddish; three kinds of nematocysts; diameter of largest less than o 0105 mm.; embryonic chitinous membrane spherical, with very short spines; spermaries on any part of body except the stalk; sexual activity more frequent in winter Hydra oligactis Pullns (H. fusca L.) ij66. By some it is claimed that H. oligaciis is strictly dioe- cious and is in this way distinct from the following species. Fig. 584. Bydra oligaciis. (a) Nematocysts. (b) Embryonic chitinous membrane. X 47. (After Brauer.)
. Fresh-water biology. Freshwater biology. HYDRA AND OTHER FRESH-WATER HYDROZOA 321 7 (8) Gray, brown, or reddish; three kinds of nematocysts; diameter of largest less than o 0105 mm.; embryonic chitinous membrane spherical, with very short spines; spermaries on any part of body except the stalk; sexual activity more frequent in winter Hydra oligactis Pullns (H. fusca L.) ij66. By some it is claimed that H. oligaciis is strictly dioe- cious and is in this way distinct from the following species. Fig. 584. Bydra oligaciis. (a) Nematocysts. (b) Embryonic chitinous membrane. X 47. (After Brauer.). (7) Gray or brown; four kinds of nematocysts, diameter of largest less than mm.; embryonic chitinous membrane plano-con- vex, with only convex side covered with spines; spermaries limited to the oral third of the body; sexual activity more frequent in auttimn Hydra polypus Linnaeus 1758. Besides the differences between H. oligaciis and .0". polypus mentioned above the latter is said to be somewhat smaller and to have somewhat shorter tentacles than the former. By some the validity of any of the differing characters mentioned above is disputed, with the possible exception of the difference in the number of different kinds of nematocysts. B. pallida Beardsley, a very pale form in Colorado, and H. corala Elrod, a very large red form in Montana, may prove to belong to the species listed above, as similar variations of them are known to occur in 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 Baldwin, 1865-1945; Whipple, George Chandler, 1866-1924. joint author. New York, John Wiley & sons, inc. ; [etc. ,etc. ]
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectfreshwa, bookyear1918
