The form with concave sides approaches to C. anceps, Lundell, but it is larger, and the ends are not emarginate. I observe that Wolle's figure of C. anceps (“Desm. of U.S.,” pl. xviii., fig. 11) differs considerably from Lundell's. The convex form resembles C. parvulum, Brébisson, but is also much larger. The three outlines which I give were taken from a gathering in which the plant occurred rather plentifully. Mr. W. B. Turner informs me that he has seen from India a plant something like mine, and thought of giving to it the name of C. varians. Herr G. Lagerheim tells me that he has had my plant growing in a greenhouse at Berlin for two years: he does not mention the locality whence he procured it, but this could hardly have been New Zealand. Cosmarium curtum, var. attenuatum, Brébisson. Plate II., fig. 16. Sufficiently near to the European species, I believe, to permit identification. It will be noticed that this New Zealand form has a slightly elliptical end-view, being narrowed as seen from the side. It is just possible that this may be sufficient to distinguish it from Brébisson's plant, or, at least, to suggest that it should be named “forma compressa.” But for the present I prefer leaving it as it is, subject to future revision. In dimensions it is rather smaller than the type. Long., 35 μ; lat., 15 μ; crass., 10 μ. Otaki. Cosmarium retusum, Perty; var. læve, Roy and Bisset Plate II., fig.17. This plant differs from Perty's type in the total absence of granules. Lundell (“Desm. Suec.,” p. 36) remarks that the granules of C. retusum are not easily observed; but they are undoubtedly absent in the New Zealand as in the Japanese form. Long., 17.8 μ; lat., 13.5 μ; crass., 7 μ;. Hawke's Bay; Otaki. The dimensions given are rather smaller than those of Roy and Bisset (“Japan Desm.,” p. 195), but the plant seems to be otherwise identical. Cosmarium pachydermum, Lundell, forma intermedia Plate II., fig. 18. Long., 81 lat., 55 μ; crass., 19 μ;. Christchurch; Hawke's Bay; Kaitoke; Otaki. This plant seems to be intermediate in size between Lundell's original type and Nordstedt's “var. minus” (“Norges Desm.,” p. 18). The segments are quite round, as in the type; but in side-view they are rather narrower and more attenuated.