VASICOLA. 



[ 802 ] 



VAUCHERIA. 



especially the characters of WOOD, are given 

 under that article. Vasculose, the sub- 

 stance of which vessels are formed, is in- 

 soluble in hydrochloric and sulphuric acid, 

 and in copper solution, but is soluble in 

 boiling caustic potash. (See also CAMBIUM 

 and MEDULLA.) 



BIBL. Henfrey-Masters, J3ot.-, Sachs, 

 Bot. 



VASIC'OLA,Tatem. AgenusofHetero- 

 trichous Infusoria. Ovate, pointed behind ; 

 mouth anterior, surrounded by long cilia; 

 contained in a transparent carapace. 



V. ciliata-, pond- water. (Tatem, Mn. 

 Mic. Jn. i. 117 j Kent, Inf. 613.) 



VAUCHE'EIA,D.O. An important and 

 to the microscopist a most interesting genus 

 of Siphonacese (Oonfervoid Algas), consisting 

 of green filamentous plants growing in fresh 

 and salt water and on damp ground, charac- 

 terized by the continuity of the cavity 

 throughout the branched tubular filament 

 (sometimes several inches long) of which 

 each plant is composed, and by the modes of 

 reproduction, both by gonidia and by spores. 

 FrtwcAmVemaybe gathered on damp borders 

 in every garden, or by the sides of ditches, 

 where they form fine silky green tufts ; they 

 are very variable in form and size, so that 

 the specific distinctions heretofore laid down 

 appear to be worth little. The ordinarily 

 occurring species presents itself as a tubular 

 cell of comparatively gigantic dimensions, 

 containing more or less protoplasm, coloured 

 by chlorophyll in the form of minute gra- 

 nules applied upon the wall or occupying 

 more or less of the cavity. The green gra- 

 nules may be seen to lie imbedded in a 

 colourless protoplasm at the inner surface 

 of the cellulose wall ; and it is curious to 

 observe when the filament is accidentally 

 or intentionally ruptured that the green 

 granules which may escape are contained in 

 a mucous investment, wnich soon rounds 

 itself into a globular body, of size propor- 

 tionate to the quantity of green granules 

 extruded ; these globules sometimes even 

 exhibit a slight rolling movement, but they 

 appear ultimately to decay. Such globules 

 sometimes occur inside the filaments, when 

 the growth is unhealthy; and Itzigsohn calls 

 them spermatospheres, stating that they pro- 

 duce spermatozoids. This, like all this au- 

 thor's observations, requires confirmation. 



If the Fawc^ma-filaments are gathered at 

 a favourable epoch, or if they are cultivated 

 in a vessel of water well exposed to light, 

 the blind ends of the filaments (or rather of 



the ramifications of the filament) are found 

 very ^ densely filled with green contents, ap- 

 pearing almost black ; and if these ends are 

 watched early in the morning, a remarkable 

 series of phenomena is observed in them. 

 The ends of the filaments about to produce 

 gonidia are found swollen into a slightly 

 clavate form ; the green contents of the club 

 separate from the general contents of the 

 filament, leaving a transparent space (fig. 

 793) ; then, having as it were acquired 

 a definite independence, the isolated mass 

 returns so as to fill up the transverse light 

 space, but does not again coalesce with the 

 lower mass of contents. Next, a light space 

 is ^observed between the surface of the ter- 

 minal body of contents and the cellulose 



Fig. 793. 



Fig. 794. 



Vaucheria Ungeri. 



Fig.- 793. End of a filament in which a gonidium is 

 being developed. 

 Fig. 794. GFonidium escaping from the filament. 



Magnified 50 diameters. 



wall surrounding it ; and the latter soon 

 gives away at the apex, forming a passage 

 for the escape of the contents. This mass 

 of contents is now clearly recognizable as the 

 gonidium or zoospore ; it gradually extri- 

 cates itself from the tube, with a rotatory 

 motion around its own axis ; and it exhibits 

 a remarkable elasticity of structure, giving 

 way and altering its form (fig. 794) to 

 squeeze through the narrow orifice of es- 

 cape. Sometimes it becomes "pinched " in 

 this process into two independent gonidia 

 of half the usual size. As soon as it has 

 perfectly emerged, it assumes an elliptical 

 form, increases much in size, and is seen to 

 be covered with innumerable vibratile cilia 

 (fig. 796), arising from its gelatinous (pro- 

 toplasmic) coat (these are rendered much 

 more distinct by applying tincture of 



