GROUP i. THALLOPHYTA: FUNGI. 



281 







nothrix-form ; or the individuals may form cubical masses, as in 

 Sarcina Ventriculi. Some forms (e.g. Bacillus, Spirillum, and 

 some Coccus-forms) are capable of locomotion";- they are provided 

 with one (Coccus-form) or more 

 (one or more at each end in Bac- 

 illus and Spirillum-forms) vibratile 

 cilia, by means of which movement 

 is effected. 



A remarkable phase, common to 

 the life-history of nearly all forms, 

 more especially the unicellular, is 

 the zoogloea-stage. It consists of 

 great numbers of cells held toge'ther 

 by bulky mucilage, to form either 

 a membrane (e.g. the scum on 

 putrefying liquids) or masses of the most various form. A striking 

 zoogloea-stage is that known as Leucoriostoc mesenterioideSj which 

 consists of wavy chains of cocci imbedded in a mass of mucilage, 

 the whole resembling the structure of Nostoc ini the Cyanophycese 

 (Fig. 136, A, B). 



Although a special name has been given to each of the multi- 

 farious forms assumed by the Schizomycetes, it must not be 

 assumed that each form to which a name has been given con- 



FIG. 162. pifferent forms of Schizo- 

 mycetes : a Micrococcus ; b Bacterium ; 

 c Bacillus with spores; d Spirillum 

 (diag.: x600). 



FIG. 163. Bacillus subtilts: A zooglcea-stage; B motile stage; C zooglcea-stage, with 

 spore-formation. After Strasburger : x 800.) 



stitutes a distinct species. On the contrary, the Schizomycetes 

 are highly polymorphic, and the various simpldr forms are, for 



