

CLASSIFICATION 3 



(d) Spirochaeta. Cells with long flexible spiral threads, 

 without flagella. Some move by means of an undulating 

 membrane. These have been thought to belong to the 

 bacteria but those that move by an undulating membrane 

 should be. classified with the protozoa. 



IV. MYCOBACTERIACE^S. Cells as short or long filaments, 

 which are often cylindrical, clavate (club-shaped), cuneate 

 or irregular in outline, and display true or false branching. 

 Spores are not formed, but gonidia are. They have no fla- 

 gella, and division takes place at right angles to the long 

 axis. There is no surrounding sheath as in the next family (V) . 



(a) Mycobacterium, Cells are short cylindrical rods, some- 

 times wedge-like, bent, or Y-shaped : long and filamentous. 

 They exhibit true branching, and perhaps produce coccoid 

 elements and gonidia, but no flagella. The Corynebac- 

 terium of Lehmann and Neumann belongs to this group. 

 Many are acid-fast. 



(b) Streptothrix or Actinomyces (ray fungus) are long 

 mycelial threads, that radiate in indian-club, or loop-like 

 forms, with true branching and delicate sheaths, devoid of 

 gonidia and flagella. Growth coherent, mould-like and 

 dry. Often powdery on the surface in culture media, 

 frequently emitting a musty odor. A few species are 

 weakly acid-fast. 



V. CHLAMYDOBACTERIACE^:. Sheathed bacteria. Cells 

 are characterized by an enveloping sheath about branched 

 and unbranched threads. Division takes place at right 

 angles to the long axis of the cells. 



(a) Cladothrix are distinguished by false dichotomous 

 branching. Multiplication is affected by separation of 

 whole branches, and by swarm spores or motile gonidia 

 having flagella. 



