go SULPHUR BACTERIA 



Family 2. AchromatiacecE. — Free, motile, cells normally 

 spherical or spheroidal in form : reproduction by 

 fission and by zoospores. 



Genus i , Achromatium. — Cylindrical, ellipsoidal, cells ; 

 reproduction by fission and by zoospores ; move- 

 ment chiefly of translation and slow. 



Genus 2. Thiophysa. Cells globular, or ovoid, uni- 

 and diplo-cocci common ; movements by trans- 

 lation and rotation ; reproduction by fission. 



Genus 3. Thiosphccrella. — Ellipsoidal cells ; thick 

 membrane surrounded by slime ; movement slow ; 

 reproduction by fission. 



Genus 4. Thioviduin. — Oblate spheroid or this figure 

 with one end slightly elongated ; reproduction 

 by fission and division at right angles to long axis. 



Family 3. Thiospirillacece. — Free, spiral, cells ; polar cilia. 



Genus i. Thiospirillum.—Free, motile, spiral, cells; 

 division by fission. . 



Family 4. Thiohacillacecc. — Short rods ; division by fission. 



Genus l. Thiobacillus. — Peritrich ciliation. 

 Genus 2. Thiopseudomonas. — Polar ciliation. 



B. Rhodo-Thiobacteria. — Seven families. 



Family i. LankesteracecB. — Normally filamentous ; highly 

 pleomorphic, with rod, spiral, and coccal, forms ; 

 occasionally forms zoogloea?. 



Genus i. Laiikesieron. — As for family. 



Family 2. Chromaiacece. — Spherical, or ellipsoidal, free cells ; 

 one polar (probably compound) cilium. 



Genus I. Chromatimn. — Rose-pink colour; uni-cocci ; 

 reproduction by fission, and probably also by sexual 

 cells. 

 Genus 2. Thioporphyra. — Purple colour ; uni-, diplo-, 

 and tri-cocci ; reproduction by fission, by budding, 

 and probably by endospores. 



