In some cases both the nucleus and the chromatophores may be carried along in the rotating stream, but in others, such as T.Titeila, the chloroplasts may remain motionless iii a non-motile layer of the cytoplasm in direct contact with the cell wall.i Desmids, Diatoms and Oscillaria show creeping movements probably due to the secretion of slime by the cells; the swarmspores and plasmodium of the Myxomycetes exhibit amoehoid movements; and the motile spores of Fungi and Algae, the spermatozoids of mosses, ferns, &c., move by means of delicate prolongations, cilia or flagella cf the protoplast.
+h,r, 1)s~,~s-s Diatoms and Desmids, according to recent researches, the thickenings on the outer walls of the cells are due to the passage of protoplasm from the interior of the cell to the outside, through pores which are found perforating the wall on all sides.
Ordinary diatoms and desmids may be mounted on mica, as above described, by putting a portion in a vessel of water and exposing it to sunlight, when they rise to the surface, and may be thus removed comparatively free from dirt or impurity.
In Ulva and Mesocarpus the chromatophore is a single plate, which in the latter genus places its edge towards the incident light; in Spirogyra they are spiral bands embedded in the primordial utricle; in Zygnema they are a pair of stellate masses, the rays of which branch peripherally; in Oedogonium they are longitudinally-disposed anastomosing bands; in Desmids plates with irregular margins; in Cladophora polyhedral plates; in Vaucheria minute elliptical bodies occurring in immense numbers.
C. Cooke, British Freshwater Algae (2 vols., London, 1882-1884), British Desmids (London, 1887); G.