30 



CELL STRUCTURES 



may possess a bundle of flagella at one end and are called 

 lophotrichic (Fig. 23) /0(/)07, lophos = tuft). Sometimes at 

 approaching division the flagella may be at both ends and are 

 then amyhitrichic (Fig. 24) {o.fj^c amphi = both). It 



is 



Fig. 22. — A bacterium showing a 

 single flagellum at the end — mono- 

 trichic. 



Fig. 23. — A bacterium showing 

 a bundle of four flagella at the end 

 — lophotrichic. 



probable that this condition does not persist long but repre- 

 sents the development of flagella at one end of each of a pair 

 resulting from division of an organism which has flagella at 

 one end only. In many bacteria the flagella arise from all 



Fig. 24. — A bacterium showing 

 flagella at each end— amphitrichic. 



Fig. 25. — A bacterium showing 

 flagella all around — peritrichic. 



parts of the surface of the cell. Such bacteria are yeritrichic 

 (Figs. 25, 26) ij^^p^f peri = around). The position and even 

 the number of the flagella are very constant for each kind and 

 are of decided value in identification. 



