246 



PL.^.NT STI'DIKS 



be solitary or several in a cell, and form \ ery striking and 

 conspleuous objects (Figs. 213, 2lo). 



Spiroiji/ra and its associates are fnrtlier j)cculiar in pro- 

 ducing no asexual spores, and also in the method of sexual 

 reproduction. Two adjacent filaments put out tubular 

 processes toward one another. A cell of one filament sends 

 out a process which seeks to meet a corrcsjjonding process 

 from a cell of the other filament. AVlien the tips of two 

 such processes come together, the end walls disappear, 



; ^14. ■'<p/r<if/;/ril. slmwiiiL' soinc ('(■niiiioii cMTpl idiis, Al .1 Iwo cells )i:ivi> hrcn 

 COIillrilnl \>y :i lillir, lull willHJiil I'lisiMli ii ZVL'iilr lills lirrli orLl.'ini/.rcl 111 carli itII; 

 also, (lie n|i|irr ,■,■11 In llir I, ■ft Ikis .■ll|,^lll|.h^,l 1,1 ,;niijiiL':ll,^ uilll till' icll t,i llll' 

 riviit. At /; tli,T,^ ar,^ ,^,^lls fr tlir,^,^ tihiiiicnls, the ells iif Uie rciitfal uiie hav- 

 ing C,)ll,illl,'alc,l W itll I.Hitll lit" tlK- Otliufs. — ( 'At, DWELL. 



and a continuous tube extending between the two cells is 

 organized (Figs. 21:!, 3 14). When many of the cells of two 

 parallel filaments l)i'c(ime thus united, tlie appearance is 

 that of a ladder, with the filaments as the side pieces, and 

 the connecting tubes as tlie i-oiinds. 



While the connecting tidie is being devt'luped the con- 

 tents of the two cells are organizing, and after the comple- 

 tion of tlie tube the contents of one cell pass through and 

 enter the other cell, fuse with its contents, and a sexual 



