Page:Transactions NZ Institute Volume 14.djvu/370

292 Cladophora, sp. n. (1), I found in gently flowing water, attached by a short stem to a piece of iron pipe. It is nearly spherical in shape, about $1⁄12$″ in diameter, tufted, green. Filaments bright green, alternately branched, articulations 1½ to 2 times longer than broad, slightly constricted at the nodes. Branches of two kinds—chætophorous, of which the articulations are 2–3 times longer than broad, filled with endochrome, ending in elongated bristly processes; and sporiferous with articulations constricted at the nodes, cells from ½ to 1½ times as long as broad, terminal cells sometimes clubbed. Capsular fructification on some of the rami either terminal or shortly stipitate. Fig. 2.

Cladophora, sp. n. (2). Filaments have a distinct gelatinous investment. Cells three times longer than broad. Here and there, mostly at attachment of rami, occur large hexagonal cells, very like the inflated cells of Œdogonium, containing a circular spore. Terminal cells elongated, tapering to a rounded point. Antheridial cells broader than long, spores subglobose, compressed. Free zoospores I have seen only once, and failed to discover cilia. Fig. 3.

1. Spirogyra communis, H., xviii.

quinina, H., xxviii.

nitida, H., xxii.

interrupta, H., xxi.

rostrata, H., xxiii.

quadrata, H., xxxvii.

pellucida, H., xxv.

sp. (?)

2. Zygnema cruciata, H., xxxviii.

This family is tolerably abundant in the locality. I have, I think, been able to discriminate all the species that have come under my observation, with one exception. In this specimen the band of endochrome commences at one end of the cell, and after making a spiral and a half reaches the further extremity of the cell, where it bends upon itself, and after another spiral and a half reaches the end from which it started; here it bends a second time, and finally terminates at the opposite end of the cell, forming altogether a series of figure-of-8 knots. Fig. 4.

In this family the normal mode of reproduction is by the conjugation of cells of distinct filiaments; it is distinctly diœcious. In certain cases, however, and they are not uncommon, the endochrome of a filament appears to have the power of self-fertilization, and spores are formed in the cells either with or without communication with contiguous cells. In this process we have a close analogy with the peculiar phenomenon of