Cosmarium regnesi, Reinsch, var. ornatum, var. nov. Plate II., fig.25. Frond very minute; constriction shallow, wide, and curvilinear; segments in front-view irregular, sides very short, cut into three minute lobules with concave edges; angles between the lobules sharp; ends concave. Cytioderm bearing at each side of each segment three granules arranged triangularly. Segments in side-view sub-fusiform, tapering gradually to rounded ends; two minute granules visible on the face and two others on each edge: of the last, one pair are near the base, the other near the end. End-view angular-elliptical, a minute granule marking each quasi-angle. Long., 9 μ; lat., 9 μ; crass., 2.5 μ. Christchurch. If I may judge by a tracing sent to me by Mr. W. B. Turner of Reinsch's original figure of this plant, and by a figure of Mr. Turner's in the, “Naturalist,” February, 1886, the plant herein described is more ornate than the original. Some specimens, however, in slides sent me from England a few years ago by Mr. Joshua, are nearer to this New Zealand form, though not exactly similar. Reinsch's figure is, as I understand, by no means a good one. The plant is exceedingly minute, and is scarcely to be made out with a less power than 1,000 diameters. It appears to have sometimes a pink tinge. Cosmarium holmiense, Lundell, forma minor. Plate III., fig. 26. Long., 54 μ; lat., 35 μ; crass., 23.7 μ. Hawke's Bay. Shorter, and not quite as wide as the original type. The American form (Wolle, “Desm. of U.S.,” p. 68) is even narrower. The dimensions here given are constant in many specimens. Cosmarium, naegelianum, Brébisson, var. latum, var. nov. Plate III., fig. 27. Frond small; constriction deep, linear, narrowed at the mouth; segments in front-view nearly twice as wide as long, with slightly convergent sides; edges crenulate, with five crenations at each side; ends wide, plane, or very obscurely crenulated. In side-view, segments sub-rectangular, angles rounded; in end-view elliptical, with a very slight median inflation and an obscurely crenulate edge. Cytioderm minutely punctate, the puncta obscurely arranged in transverse rows when in side-view. Zygospore globose, spinous with short sharp subulate spines. Long., 25 μ; lat., 23.8 μ;, crass., 11 μ; diam. zygosp. incl. spin., 32.7 μ; long. spin., 3 μ.