. The Cambridge natural history. Zoology. FRESH-WATER MEDUSAE 2Q3 suggested the view that Limnocodium is not properly placed in any of the other orders. Goto/ however, in a recent paper, confirms the view of the affinities of Limnocodium with the Olindiidae. The life-history of Limnocodium is not known, but a curious Hydroid form attached to Fontederia roots was found in tlie same tank as the Medusae, and this in all probability represents the hydrosome stage of its development. The Medusae are formed apparently by a process of transverse fission of the Hydroid stock ^ similar in some respects
. The Cambridge natural history. Zoology. FRESH-WATER MEDUSAE 2Q3 suggested the view that Limnocodium is not properly placed in any of the other orders. Goto/ however, in a recent paper, confirms the view of the affinities of Limnocodium with the Olindiidae. The life-history of Limnocodium is not known, but a curious Hydroid form attached to Fontederia roots was found in tlie same tank as the Medusae, and this in all probability represents the hydrosome stage of its development. The Medusae are formed apparently by a process of transverse fission of the Hydroid stock ^ similar in some respects to that observed in the production of certain Acraspedote Medusae. This is quite unlike the asexual mode of formation of Medusae in any other Craspedote form. The structure of this hydrosome is, moreover, very different to that of any other Hydroid, and consequently the relations of the genus with the Trachomedusae cannot be re- garded as very close. Limnocodium has only been found in the somewhat artificial conditions of the tanks in botanical gardens, and its native locality is not known, but its association with the Victoria regia water-lily seems to indicate that its home is in tropical South America. Limnocnida tanganyicae is another remarkable fresh-water Medusa, about seven-eights of an inch in diameter, found in the lakes Tanganyika and Victoria Nyanza of Central Africa.' It differs from Limnocodium in having a short collar-like manu- brium with a large round mouth two-thirds the diameter of the umbrella, and in several other not unimportant particulars. It produces in May and June a large number of Medusa-buds by gemmation on the manubrium, and in August and September the sexual organs are formed in the same situation. The fixed hydrosome stage, if such a stage occurs in the life- history, has not been discovered; but Mr. Moore * behoves that. Fio. 140.—Limnocnida tanganyicae. X 2. (After Guuther.) ' S. Goto, ^ G. H. Fowler, Quart. Journ. Micr. Sci. xxx. 1890,
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