Miscellaneous, 373 Dimorphic Development and Alternation of Generations in the Cladocera. Dr, G. 0. Sars has discovered a remarkable dimorphism and alternation] of generations in Leptodora hijalina (" Om en dimorph Udvikling samt Generationsvexel hos Leptodora," Forhandlinger Vidensk.-Selsk. Christiania for 1873, p. 15, and plate). The de-velopment from the ordinary summer-eggs, as already described by E. P. Miiller, is without metamorphosis and like that of ordinary Cladocera, the young when excluded from the egg agreeing essen-tially with the adult ; while, according to Sars's observations, the young are excluded from the winter-eggs in a very imperfect con-dition, quite unlike the kno^vn young of any other Cladocera, and pass through a marked postembryonal metamorphosis. In the earliest observed stage of the young of this form, the body is obovate, whoUy without segmentation, the compound eye wanting, while there is a simple eye between the bases of the antennulaj, the swimming-arms (antenna)) well developed, and the six paii-s of legs represented only by minute processes projecting scarcely beyond the sides of the body. But the most remarkable feature is the presence of a pair of appendages tipped with cilia and nearly as long as the body, which are evidently homologous with the mandibular palpi of other Crustaceans, although these apjiendages have always been supposed to be wanting in the species of Cladocera. Two subsequent stages, gradually approaching the adult form, are described. The adults from the winter-eggs have no vestige of the mandibular palpi left ; yet the simple eye (which is wholly absent in ordinary indi-viduals developed from summer-eggs) is persistent, and thus marks a distinct generation. Three stages of the young from winter-eggs are beautifully figured upon the plate accompanying the memoir. This remarkable species has, still more recently, been made the subject of a very elaborate memoir by Prof. Weismann of Freiburg ("Uebcr Eau und Lebenserscheinungen von Leptodora hyalina" Zeit-schrift fiir wissensch. Zool. xxiv., Sept. 1874, pp. 349-418, plates 33-38), who, however, had not observed the peculiar development of the winter-eggs. The occurrence of this genus in Lake Superior is noticed in this Journal, vol. vii. p. 161, 1874. — Silliman's Ame-rican Jovrnal, March 1875. On the Actinia? of the. Oceanic Coasts of France. By M. P. Fischer. The Actiniae of the oceanic coasts of France (comprising in that geographical region the Anglo-Xorman isles) number thirty-one species : — Cerianthns membranaceus, Gmelin ; Edwardsia Harassii, Quatrefages ; E. tiimida, Quatref. ; E. Beautempsi, Quatref. ; E. callimorpha, Gosse ; Halcampa chrysanthelluni, Peach ; Peachia tirulata, Gosse; P. triphylla, Gosse; Anemonia sulcata, Pennant; Aiptasia Co?<c7u', Cocks ; Actinia equina, \JixmQ; Metridiuni dian-/7«t5, Ellis ; Cereiis 2>^diiyindatus, Tcunant ; Sar/artia nivea, Gosse; S. viduata, Miiller (including S. troghdi/tes, Johnston) ; S. venusta, Ann. & Mag. N. Hist. Ser. 4. Vol. xv. 20
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