Christchurch; Hawke's Bay; Otaki. A plant of the series of C. crenatum, Ralfs; but proportionately shorter and broader, and the crenulations of the ends in front-view are so obscure that the end often, appears nearly straight. C. naegelianum, as figured by Wolle (“Desm. of U.S.”), is narrower than this New Zealand form, but his description otherwise corresponds. This plant differs from C, sub-punctulatum, Nordstedt (“Alg. of N.Z.,” p. 47), in the absence of the granules which are conspicuous in that form. The zygospore is new. Cosmarium turnerianum, sp. nov. Plate III., fig. 28. Frond moderate; segments in front-view twice as broad as long, or more; constriction deep, linear, and somewhat wide, so that the segments do not closely approximate; segments sometimes circular, sometimes trapezoidal, the edges deeply sinuous with ten wide crenulations; cytioderm marked by a number of granular inflations corresponding to the crenulations of the edge, giving an appearance to the frond of grooves radiating from the centre; in the median space a series of seven smaller inflations in a row on the base of each segment. A frond with circular segments is almost regularly elliptical, the ends at the constriction somewhat sharp. In side-view, segments sub-elliptical, narrow, ends rounded, edges very obscurely crenulated towards the ends, and with a slight inflation towards the base marked with minute inflations. In end-view, frond sub-elliptical with sharp ends, the thickness variable; a slight median inflation visible, and the granules arranged in transverse series. Long., 36–40 μ; lat., 40 μ; crass., 14–20 μ. Hawke's Bay. This plant approaches C. cyclicum, Lundell, especially when elliptical with rounded segments, but it is smaller, has a wider sinus at the constriction, with more conspicuous “grooves” on the frond, and the row of granules at the base of each segment, producing the inflation in side-view, is quite distinctive. Lundell gives two variant figures of C. cyclicum, neither of which has trapezoidal segments. C. cyclicum, var. arcticum, Nordstedt, is more angular than Lundell's type, but its edges are irregularly incised, and it has not the rows of granules which produce the inflations of our species. I have ventured to attach to this plant the name of Mr. W. B. Turner, who has been kind enough to give me much help. Cosmarium sub-cyclicum, sp. nov. Plate III., fig. 29. In 1882 (“Trans.” vol. xv., p. 241) I reported this plant under the name C. cyclicum, var. ampliatum Professor Nordstedt suggests to me that it should rather be a new species,