Olive, Mitotic division of tlie uuclei of tlie Cyauopliyceae. 33 



tlie arrangement in tlie elongating cell of tlie chromatin gra- 

 nules in a spireme tliread. In tlie opinion of tlie writer, tliere- 

 fore, the nearest approacli to a resting state of tlie nncleus, 

 linder tlie iisnal eonditions, at least, is probably best illustrated 

 by figs. 62 and 6-i, in wliicli tlie daugliter cliromosomes reniain 

 separate and distinct, and surrounded by achromatin, until rear- 

 ranged in a spireme for tlie next division. A breaking up into 

 smaller graniües of clironiatin and the formation of a reticiüuni 

 such as is characteristic of the nuclei of higher organisms is 

 not evident; and no nuclear sap is secreted, consequently there 

 is no limiting membrane. It is possible, however, that iig. 16 

 illiistrates a nearer approacli tlian is usual to a normal resting 

 eondition; and that hg. 33 sliows the beginnings of the form- 

 ation of karyolymph (or the Spaces may be occupied by slime 

 giobules?); and fui-ther, that in certain cells of figs. 6 and 14, 

 the nuclei have entered partially into a state of rest. 



Cell iiiclusioiis. 



In the foregoing pages, mention lias been offen mad-e of 

 cyanophycin granules (a name given by Borzi) and slime giob- 

 ules (Palla), or .,Zentralkörner" (Zacharias) whicli occm- so 

 abundantly in the cells of the Cyanophyceae. It is highly pro- 

 bable, in fact, that the cyanophycin granules are a type of reserve 

 food material peculiar to these plants; wliile the slime giobules 

 have a niuch wider distribution, having been found by Bütschli 

 in Diatoms, Flagellates, in the epidermal cells of Phanero- 

 gams, etc. 



Minute plastids — the „Cyanoplasts", as called by Hegler 

 — are said by several investigators to be present and to contain 

 the gTeen and blue coloring matters. The writer agrees with 

 Fischer, however, that the coloring matters are lield, not in 

 plastids, but diffused in a peripheral Chromat opliore. He gier, 

 in liis article, added another substance — glycogen — to our 

 list of the cell inclusions of the Cyanophijceae] and Kohl (03) 

 confii-med liis discovery, giving a list of twelve genera in which 

 glycogen occurs. It is the opinion of botli Hegler and Kohl 

 that this substance is the first perceptible product of assimilation 

 in the blue green algae. I have not yet been able, however, 

 after many careful tests niade both with sections as well as with 

 fresh filaments, successfully to demonstrate glycogen in OsciUa- 

 toria. Equally misuccessful have been many tests with sudan 

 and other reagents, made also with Oscillaforio, for the purpose 

 of determining the presence of the minute fatty oil giobules, 

 said by Zacharias and Kohl to occur in the cytoplasm of 

 TohjpotJn-ix. 



It is not the purpose of this paper to discuss the coiiipo- 

 sition or the probable function of the two kinds of graniüar 

 inclusions of the cytoplasm which have been found by the writer 

 in all the forms studied, since the microchemical tests which I 

 have so far made wiU not Warrant definite conclusions. Attention 



Beihefte Bot. Centralbl. Bd. XVIU. Abt. 1. Heft 1. '^ 



