. Algæ. Vol. I. Myxophyceæ, Peridinieæ, Bacillarieæ, Chlorophyceæ, together with a brief summary of the occurrence and distribution of freshwat4er Algæ . yielded a quantity of a form ofNodularia turicensis. The conditions under which the soil had been kept, and the culturesmade, were such that no outside contamination could have taken place, and therefore the smallspores of this species (only 7 /u by 8/x) must have retained their vitality for a period of 66 spores were indeed resting-spores Germination of resting-spores a gradually widening aperture and then is itself exuded as an e
. Algæ. Vol. I. Myxophyceæ, Peridinieæ, Bacillarieæ, Chlorophyceæ, together with a brief summary of the occurrence and distribution of freshwat4er Algæ . yielded a quantity of a form ofNodularia turicensis. The conditions under which the soil had been kept, and the culturesmade, were such that no outside contamination could have taken place, and therefore the smallspores of this species (only 7 /u by 8/x) must have retained their vitality for a period of 66 spores were indeed resting-spores Germination of resting-spores a gradually widening aperture and then is itself exuded as an envelopefor the escaped cell. The latter now begins to divide and forms a newplant. (Fig. 18, A, B, and C.) (2) The first division of the protoplast occurs within the walls of thespore, and this may be followed by other divisions, so that from two to fourcells may be formed before the spore-wall is burst open. Succeedingdivisions then cause the free end of the young filament to extend furtherand further from the spore, although the other extremity may not freeitself from the old spore-wall for some time. (Fig. 18^1, the lowest sporein the figure.). Fig. 18. A and B, germination of the spores of Anab&na azoll& Strasb.; A, x 680; B, x 850(after Fritsch). In A, two spores show germination of the first type, and the lowest sporegermination of the second type. In B, variations of the first type of germination are and 7), germination of the spores of Anabfena cycadearum Eeinke; C illustrates the firsttype of germination and D the third type; x 2200 (after Spratt). E, germination of a sporeof Oscillatoria sp. (possibly 0. limosa Ag.); x about 700 (after Phillips). (3) Both walls of the spore may swell up and become mucilaginous,forming a gelatinous envelope of considerable dimensions. The protoplastsooner or later begins its division within this wide coat of mucus. (Fig. 18 D.) The first type of germination occurs more frequently than the other Anabfena and Nodular
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