. Fresh-water biology. Freshwater biology. Microhydra Potts. But one species, M. ryderi Potts, first described from near Philadel- phia, Pa., but since then found in different locaUties in Europe. The medusae have been seen only when in a very early stage and the adult stages are not known. Fig. sS?. Microhydraryderi. (a) Young medusa. X 40. (After Moore from Potts.) {h) Hydranths and embryo. (J J X 22. (After Ryder from Potts.) 12 (11) Hydranth form rarely seen; medusae have more than eight tentacles. Craspedacusta Lankester. But one species, C. sowerbyi Lankester, known in Europe and America
. Fresh-water biology. Freshwater biology. Microhydra Potts. But one species, M. ryderi Potts, first described from near Philadel- phia, Pa., but since then found in different locaUties in Europe. The medusae have been seen only when in a very early stage and the adult stages are not known. Fig. sS?. Microhydraryderi. (a) Young medusa. X 40. (After Moore from Potts.) {h) Hydranths and embryo. (J J X 22. (After Ryder from Potts.) 12 (11) Hydranth form rarely seen; medusae have more than eight tentacles. Craspedacusta Lankester. But one species, C. sowerbyi Lankester, known in Europe and America. Found only in aquaria according to earlier records, but large numbers were collected by Professor H. Gar- man in September, 1916, in a creek near Frankfort, Kentucky, the first record of their occurrence in other than artificial sur- roundings. A second species, C. kawaii Oka, has been found in a river of China. Fig. 588. Craspedacusta sowerbyi. X about 4. (After Hargitt.) Limnocnida Giinther is the only other known genus of fresh-water medusae and its distribution so far as recorded is limited to the Eastern Hemisphere. Limnocnida tanganyicae (Bohm) 1883 is found in Africa; Limnocnida indica Annandale iiji2, in India; Limnocnida rhodesia Boulenger 1912, in southern IMPORTANT REFERENCES ON FRESH-WATER HYDROZOA Braxjer, a. igop. Die Benennung und Unterscheidung der Hydra-Arten. Zool. Anz., 33: 790-792. Downing, E. R. 1905. The Spermatogenesis of Hydra. Zool. Jahrb., Anat., 21: 379-426. Hargitt, C. W. 1908. Occurrence of the Fresh-water Medusa, Limnoco- dium, in the United States. Biol. Bull., 14: 304-318. Nutting, C. C. 1901. The Hydroids of the Woods Hole Region. U. S. Fish Com. BuU. for 1899: 327. Potts, E. 1906. On the Medusa of Microhydra ryderi and on the Known Forms of Medusae inhabiting Fresh Water. Quar. Jour. Mic. Sci., 50: 623-633; 2 pi. Smith, F. 1910, Hydroids in the Illinois River. Biol. Bull., 18: Please note that these images are extracted from
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