. Algæ. Vol. I. Myxophyceæ, Peridinieæ, Bacillarieæ, Chlorophyceæ, together with a brief summary of the occurrence and distribution of freshwat4er Algæ . stauros. B and C, valve andgirdle views respectively ofSchizostauron Crucicula the forked x 500. v, valve; iv.,intercalary valve with shortsepta (s) ; cb., connectingband. The fine striations onthe valves are not shown inthe figures. 92 BacillariesB termed the axial area and varies much in width. Less often, smooth areasoccur parallel to the axial area but nearer the margin of the valve; theseare known as lateral area
. Algæ. Vol. I. Myxophyceæ, Peridinieæ, Bacillarieæ, Chlorophyceæ, together with a brief summary of the occurrence and distribution of freshwat4er Algæ . stauros. B and C, valve andgirdle views respectively ofSchizostauron Crucicula the forked x 500. v, valve; iv.,intercalary valve with shortsepta (s) ; cb., connectingband. The fine striations onthe valves are not shown inthe figures. 92 BacillariesB termed the axial area and varies much in width. Less often, smooth areasoccur parallel to the axial area but nearer the margin of the valve; theseare known as lateral areas. The raphe (or median line) may be straight, undulating, or its most highly developed state it is a fissure of a more or less complicatedcharacter by which the protoplast is placed in contact with the surroundingmedium. In the Naviculacese the cleft of the raphe is not in a verticalplane, but is always bent, and not infrequently V-shaped in cross-section.(Consult fig. 65 5). Moreover, the cleft is not wholly open, being in many. Fig. 65. Navicula (§ Pinnularia) viridis Ktitz. 2, diagram with the raphe of one valve almostsuperimposed upon the other ; ekn, terminal nodule ; ckn, central nodule. 2, longitudinalsection through the central nodule showing the two canals (vk) joining the outer («) andinner (i) clefts of each half of the raphe ; schl, the canal which joins both halves of the innerfissure. 3, terminal nodule showing ends of the two fissures of the raphe; isp, inner fissureterminating in the funnel-shaped body (tk); asp, outer fissure ending in the polar cleft (psp).4, superimposed terminal nodules of epivalve and hypovalve. 5, transverse section acrossthe cell, showing the inner (isp) and outer (asp) fissures of the raphe (r), the nature of thecostse in the valves, and the disposition of the two chroma tophores. (From Oltmanns ;1—4, after 0. Miiller ; 5, after Lauterborn.) forms closed in its middle region; that is, along the bend (or in cross-sec
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Keywords: ., bookcentury1900, bookdecade1910, bookpublishercambridgeengtheuni
