94 



Elementary Biology. 



connected, and showing large intercellular spaces ; in Fucus 

 only the medullary portion of its mass is so constituted. 



The thallus does not long retain its white appearance, it 

 soon begins to show greenish patches at intervals over its 



FIG. 28. Eurotium repens. (De Bary.) 

 Jt 



A, portion of thallus with erect spore-bearing filament (c); young 

 ovarium (as). B, young ovarium (as) and spermarium (/j. C, same 

 beginning to be surrounded by sterile filaments, two shown in the 

 front. D, ' fructification.' 



surface. We must now endeavour to throw some light on 

 this phenomenon. Microscopic examination of a portion of 

 the thallus which shows this alteration in colour demonstrates 



