. Algæ. Vol. I. Myxophyceæ, Peridinieæ, Bacillarieæ, Chlorophyceæ, together with a brief summary of the occurrence and distribution of freshwat4er Algæ . sometimes consisting of two loosely con-nected halves. Sub-fain. Phacotese. b. Cells aggregated to form crenobia with very definite characters. Sub-fain. Volvocess. Sub-family CARTERIE/E. All theequal cilia attached to the anteriorend of the cell. The principal genusis Carteria, in which the cells arespherical, ovoid or ellipsoid, and pro-vided with a thin cell-wall. Near theattachment of the cilia are two smallcontractile vacuoles; and a con
. Algæ. Vol. I. Myxophyceæ, Peridinieæ, Bacillarieæ, Chlorophyceæ, together with a brief summary of the occurrence and distribution of freshwat4er Algæ . sometimes consisting of two loosely con-nected halves. Sub-fain. Phacotese. b. Cells aggregated to form crenobia with very definite characters. Sub-fain. Volvocess. Sub-family CARTERIE/E. All theequal cilia attached to the anteriorend of the cell. The principal genusis Carteria, in which the cells arespherical, ovoid or ellipsoid, and pro-vided with a thin cell-wall. Near theattachment of the cilia are two smallcontractile vacuoles; and a conspicuouspigment-spot is present, although itsposition is variable. The chloroplastis large and massive, hollowed outanteriorly into the form of a basin orcup, and is usually furnished with asingle conspicuous pyrenoid in its pos-terior thicker part (fig. 98 A and B).The presence of four cilia is the onlyfeature distinguishing this genus fromChlamydomonas. In the formationof zoogonidia the first division-planeis longitudinal or slightly several species quadriciliatedisogametes are also known, which genera of this sub-family possess four. A—G, Carterin »mW/i«s(Fresen.)Dill;A and B, vegetative cells (= zoogonidia); C,four daughter-cells within old wall of mother-cell; D, gametes; E, conjugating gametes;F, zygote. H and /, Chlamydomonas Debary-ana Gorosch. J and A, Chi. grandis Stein(= Chi. Kleinii Schrnidle). All x 475. cv, con-tractile vacuoles; n, nucleus; p, pyrenoid;zg, gamete; z, zygote. 1 In Agloe there is an additional group of three contractile vacuoles at the posterior end ofthe cell (vide Pascher, 12). 170 Volvocineae
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