. Algæ. Vol. I. Myxophyceæ, Peridinieæ, Bacillarieæ, Chlorophyceæ, together with a brief summary of the occurrence and distribution of freshwat4er Algæ . leaving the separating walls asscars along the axis. In Pseudobryopsis the leaves are from the first cutoff by a transverse wall from the axis. The cell-wall is thin and not encrusted. Wille (97) stated that trabeculaesometimes occur, such as those present in the coenocytes of Caulerpa, butthis observation is apparently doubtful. The protoplasm forms a parietallayer in which there are numerous nuclei and chloroplasts. The latter aresmall elli
. Algæ. Vol. I. Myxophyceæ, Peridinieæ, Bacillarieæ, Chlorophyceæ, together with a brief summary of the occurrence and distribution of freshwat4er Algæ . leaving the separating walls asscars along the axis. In Pseudobryopsis the leaves are from the first cutoff by a transverse wall from the axis. The cell-wall is thin and not encrusted. Wille (97) stated that trabeculaesometimes occur, such as those present in the coenocytes of Caulerpa, butthis observation is apparently doubtful. The protoplasm forms a parietallayer in which there are numerous nuclei and chloroplasts. The latter aresmall elliptic discs with a central pyrenoid. In the large cell-sap vacuolewhich occupies all the central space of the coenocyte there are rounded andspindle-shaped albuminous bodies, first observed by Noll. w. A. 15 226 Siphonales Vegetative propagation is known to occur by detached leaves whichgrow into new plants, and by the formation of rhizome-like branches fromthe lower part of the thallus. Zoogonidia are unknown. Numerous biciliated anisogametes are produced in gametangia, which inBryopsis are converted leaves but in Pseudobryopsis are ovoid or pear-. Fig. 146. 1, portion of thallus of Bryopsis cupressoides Lanix. with almost ripe gametangia (#),x about 25. 2, pinnaa of leaflet of Pseudobryopsis myura (J. Ag.) Berth, with gametangia(g); 3 and 5 a, copulation of gametes; 4, zygotes soon after copulation showing chloro-plasts of male (chr) and female (chr) gametes ; 5, zygote in which the chloroplast hasdivided ; 6, germination of zygote. (From Oltrnanns ; 2 and 3, after Berthold.) shaped outgrowths from the leaves (fig. 146 #). Male and female game-tangia may occur on the same axis or they may be on different female gametes are about three times the size of the male gametes,possessing a rather large posterior chloroplast with one pyrenoid and apigment-spot. The male gametes, which are of a brownish-red colour, haveonly a very small chloroplast and no pigment-spot.
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