sidered as a separate species. Hereafter it may be perhaps taken only as a large form of S. pulchellum. Genus Onychonema, Wallich. *Onychonema filiforme, Ehrenb. I reported this plant in 1880 under the genus Sphærozosma. Messrs. Roy and Bisset (“Japan Desm.;” p. 242) draw attention to the fact that the double processes overlap the semicells, and that the plant must therefore be placed under Onychonema. Hawke's Bay; Christchurch; Otaki. Genus Euastrum, Ehrenberg. Euastrum mammatum, sp. nov. A. Forma major, var. sub-cuneatum. Plate I., fig. 4. Frond rather large; constriction deep, somewhat widened internally; segments in front-view cuneate, margins nearly straight, but with a low inflation or mamma about half-way to the end; ends slightly protruding, and at each side of the notch emarginate; the notch is shallow, but seems as if continued in a shallow groove for nearly a quarter of the distance to the isthmus. On the surface of the frond several (seven or eight) very inconspicuous inflations in two transverse series, two of which correspond to the lateral mammæ; at the ends an inflation at each side of the notch. Cytioderm punctate. In side-view, segments tapering from a shallow constriction to narrow rounded ends; median mammæ and inflations visible. Long., 70–77 μ; lat., 35–42 μ; crass., 18–24 μ; lat. isthmi, 11μ. Hawke's Bay. B. forms minor, var. ellipticum. Plate I., fig. 4a. Frond smaller and somewhat less angular than the last; the sides slightly convex, the ends much more protuberant than in sub-cuneatum. Lateral mammæ, inflations, and groove as in the larger form. The punctca are less distinct. Ends in side-view very slightly dilated. Long., 60–67 μ; lat., 31–35 μ; crass., 20–22 μ; lat. isthmi, 12μ. Rutherford's Swamp, Otaki. Both forms of this plant approach E. cuneatum, Jenner (which also occurs in New Zealand); but they are much smaller, and the inflations, the grooves at the notch, and the protuberant ends distinguish them. Euastrum sinuosum, Lenormant. I have two formas which I refer to this species, as follow:— A. Forma major, var. gemmulosum, var. nov. Plate I., fig. 5.