70 



j-iresence in tlie cytoplasm and in the nuclei of nuiiierous 

 dark crauules. Tliece deseneratinc tetro.sporangia are eas- 

 ilj^ distinguishable even in the living condition "b- rea,son 

 of their almost hlaxk opaque appearance, and some ere to 

 "be found in every tetraspora,ngial sorus . V/liat causes lead 

 to tlieir degeneration I have not "been able to determine. 



In the normal tetrasporangia, the cleavage partitions, 

 which represent folds of the hautschicht, but which appear 

 in section as a single line except near the periphery 

 (fig. 137) , split so as to reveal clearly their double na- 

 ture. At the sajne time the cytoplasm, which lay in close 

 contact witla the partitions, separates along the line of 

 the partitions so that the cleavage furrov/s become wide 

 as well as deep (fig, 133), Even at this stage, ]io-wever, 

 tiiey ejKtend no further in than to the edge of the nucleo- 

 kinoplasmic rna.ss . Coincident witii tliese changes in the 

 partitions, the nuclei ..iiich were fl^ittened become again 

 approximately spherica,l. Vacuoles develop in the cytoplasm 

 in the centre oiff the nucleo-kinoplasmic me^ss . At tlie same 

 time, siXoll cliroj.iatophores begin to appear in the cytoplasm 

 along the outer border of the tetrasporangium. These in- 

 crease in size, and ei few extend along tiie partitions into 

 the body of the protoi.last . In this condition tj^e tetra- 



