GENERAL SYSTEMATIC BACTERIOLOGY 351 



It would seem logical to make the first named species, L. ochracea, 

 the type. This would limit the genus to the iron bacteria. The 

 mouth forms may well be placed in the genus Leptoirichia in accor- 

 dance with the proposal of Trevisan. 



This was done by Buchanan (1918, p. 303) in the description: 



Filaments of cylindric colorless cells, with a sheath at first thin and colorless, 

 later thicker, yellow or brown, becoming encrusted with iron oxide. The iron 

 may be dissolved by dilute acid, whereupon the inner cells show up well. Multi- 

 plication is through the division and abstriction of cells and motile cylindric 

 swarm cells. Swarm cells sometimes germinate in the sheath giving appearance 

 of branching. Pseudodichotomous branching may occur. 



The type species is Leptothrix ochracea (Leiblein) Kuetzing. 



Castellani and Chalmers (1919, p. 1068) give the following descrip- 

 tion of the genus and designation of type species. 



Filamentous fungi with long, very thin mycelial threads, with no capsule or 

 only a very delicate one; non-branching, non-septate, generally non-cultivable. 

 Type species. Leptothrix maxima Miller. 



Some five species are listed, all parasitic. 



Lieske (1921, p. 2) regards L. ochracea as the generic type. 



Bergey et al. (1923, p. 390) follow Buchanan including the genus 

 as the first in the family Chlamydohacteriaceae. 



Leptotrichacei. A family name used by Schroeter (1886, p. 170) 

 for Zopf's Leptotricheen (g.v.). The following genera are included: 

 Leptothrix Klitzing, Beggiatoa Trevisan and Crenothrix Cohn. 



Leptotrichaceae. The corrected form of Leptotrichacei used by 

 an abstracter (Journ. Roy. Mic. Soc, 1890, p. 758) of the work of 

 Hansgirg (1890). 



Leptotricheae. A family name given by Kuetzing (1843, p. 198) 

 to a group of algae including the genus Leptothrix. Later it was used 

 as a "generic" name by Sternberg (1892, p. 19) with the description: 



The vegetative cells present rod-shaped and spiral forms, and grow out into 

 straight, wavy or spiral filaments; these may show a difference between the two 

 extremities of base and apex. Cocci-like reproductive bodies are formed by seg- 

 mentation of the rod-shaped elements in these filaments. In some of the species 

 the segments are enclosed in a common sheath. Subgenera; Leptothrix, Beggia- 

 toa, Crenothrix, Phragmidiothrix. 



Leptotricheen. A family name used by Zopf (1885, p. 51) with the 

 following diagnosis: 



