ORDER II. CHLAMYDOBACTERIALES BUCHANAN, 1917.* 



(Buchanan, Jour. Bact., 2, 1917, 162.) 



Chla.my.do.bac.te.ri.a'les. M.L. fern. pi. n. Chlamdobacteriaceae type family of the order 

 Chlamydobacteriales ; -ales ending to denote an order ; M.L. fern. pi. n. Chlamydobacteriales the 

 Chlam ydobacteriaceae order . 



Colorless, alga-like bacteria which occur in trichomes. May or may not be ensheathed. 

 They may be unbranched or may show false branching. False branching arises from a lateral 

 displacement of the cells of the trichome within the sheath; this gives rise to a new trichome 

 so that the sheath is branched while the trichomes are separate. The sheaths may be com- 

 posed of an organic matrix impregnated with iron or manganese oxides, or they may be 

 composed of an organic matrix free from these oxides. Gram-negative. Reproduction may be 

 by flagellate swarm spores or by non-motile conidia. Endospores of the type found in Bacil- 

 lus are never developed. Fresh-water and marine forms. 



Key to the families of order Chlamydobacteriales. 



I. Conidia, when formed, are motile by means of a sub-polar tuft of flagella. 



A. Possesses trichomes in which false branching may occur. Motile swarm cells may be 

 formed. 



Family I. Chlamydobacteriaceae . p. 262. 



B. Possesses ensheathed, unbranching trichomes which may be very long (0.5 cm). 

 Found in fresh water. 



Family II. Peloplocaceae, p. 270. 

 II. Non-motile conidia are produced. 



Family III. Crenotrichaceae, p. 272. 



FAMILY I. CHLAMYDOBACTERIACEAE MIGULA, 1894. 

 (Arb. bakt. Inst. Hochschule, Karlsruhe, 1, 1894, 237.) 



Chla.my.do.bac.te.ri.a'ce.ae. Gr. noun chlamys, chlamydis a cloak; Gr. neut.n. bac- 

 terium a small rod; -aceae ending to denote a family; M.L. fem.pl.n. CJdaui ydobacteriaceae 

 the family of the sheathed bacteria. 



Bacteria which occur in trichomes and which frequently show false branching. Sheaths, 

 when present, may or may not be impregnated with ferric and/or manganese oxides. Cells 

 divide transversely. Swarm cells, if developed, are usually motile by means of a tuft of 

 flagella. Usually found in fresh water. 



Key to the genera of family Chlamydobacteriaceae. 



I. Trichomes surrounded by sheaths which are usually not impregnated with iron or 

 manganese oxides and which do not dissolve in hydrochloric acid. Large forms, mostl}^ 

 sessile. 



* Rearranged and revised by Prof. Robert S. Breed, Cornell University, Geneva, New 

 York, November, 1953; further revision, with the introduction of an additional family and 

 genera and species, by Prof. Dr. Herbert Beger, Institut fiir Wasser-, Boden- und Luft- 

 hygiene, Berlin-Dahlem, Germany, January, 1955. 



262 



