86 SULPHUR BACTERIA 



Lamprocystecc. — Cells in families : division first in three, 



then in two directions of space. 

 ThiopediecE. — Cells in families : division in two planes, 



forming plates of cells. 

 Amoehohacteriacecc. — Cells in families : division in one 



plane. 

 ChromatiecE. — Cells free, capable of swarming. 



(It is not necessary to consider the Rhodobaclerioidece in 

 this work, as they are not sulphur bacteria.) 

 Key to the Thiocapsecc : 



Genus i. Thiocysiis. — -Motile : families small, compact, 

 . enclosed singly or several, in a cyst. 

 Genus 2. Thiosphcera. — Motile : cells large (7 — 8/x), 



loosely bound by gelatine into loose families. 

 Genus 3. Thiosphcerion. — Motile : cells small, united 



to form solid, spherical families. 

 Genus 4. Thiocapsa. — Non-motile : cells spread out in 

 flat families, loosely enveloped in a common gelatine. 

 Genus 5. Thiosarcina. — Non-motile : cells in regular 

 packets. 

 Key to the Lamprocystecc : 



One genus Lamprocyslis. As for family. 

 Key to the ThiopediecB : 



Genus i. Lampropedia. — Cells arranged regularly in 



fours. 

 Genus 2. Thioderma. — Cells in a film, or membrane, not 

 regularly disposed in tetrads. 



Key to the Amoehobacteriece : 



Genus i. Aniabohacter. — Cells connected by plasma 



threads : families amoeboid, and motile. 

 Genus 2. Thiodictyon. — Cells arranged in a net by their 



ends. 

 Genus 3. Thiothece. — Cells not arranged in a net, and 



loosely aggregated in gelatine : motile. 

 Genus 4. Thiopolycoccus. — Same as the preceding, 



only cells are not motile, and closely appressed into 



a colony. 



