NOSTOC. "-IT 



with interspaces tillt'il with JV"^<. It' other al^.i liana, 



enter the cavities, the opening is neither clos.-d nor <'n> tin- walls 

 grow out as processes. Infection by .V only incurs when 



the mucilage-cavities lit- near the apex of the thallus ami 

 secreting mucilauc, tin- -ub-tanee \vhit-!i evidently stimulate- the 

 NostiH- t<> enter. 



Leitgeb found many Anthoceroteae (D< H>II\I<-> r*, A'"/"////,/.s, 

 A n fh<; ,".<) witli mucilage-cavities containing Nbstoc, nm sunk 

 in the thallu.s as with Antlun; /-\ faevis, hut forming warty pio- 

 jections above it. In the case of Dendroceros the- ..... icurred <>n 

 the upper side of the thallu.s as well as <m the lower. Tin- 

 "jM-nmgs of the cavities of Xtt!ii/l<is do not close after int'ertiun, 

 lut distinctly "pen wider. 



Janczewski observed that ehlir.)phylli.us cells nf 11,.].,! 

 tln'iiuh at first unintiuein-ed by the intruding alga, al'i'-rwards 

 lose their chlorophyll and plasma : hence he assumed that the 

 imprisoned S <(< lie-in^ in time to live a parasitic life, and to 

 kill the host-cells. This, however, i> not >upported by other 

 aiithoi'ities. (Joeb.-l, on the other hand, bclie\es that the Nbstoc, 

 like the mucilage ainoirj-! wliich il gTOV :i-eful to the 



thallus, and that it ultimately coinpletelx replaces the muci! 

 1'rantl held that the al.-a assimilated five QltTOgen, ui\inu 

 up the product to the hail's in the cavity: but thi- i- ex- 

 tremely unlikely, especially when the Nostoc \- comj.leteiy enclosed 

 in its host. 



Nbstoc lichenoides is al-o \ t -ry frequent in the leaf-auricles on 



the under >ide of the thalllis of HI, I-,',, < jnisif/,1. The aiirieles 



eontain mucilage, which probably induces ihc Nbstoc to enter. A- 

 a result of the A'"x/i- invasion the auricle enlarge- and continue- 

 i.o live, whereas without this it would soon have died oil. 

 Branched filamentous pn-c- ----- - are produced from the innei wall 



of the auricle and xi'"W amon-st the Nbstoc.* 



A'. THE TRUE ALGAE. 



In the-,!- A1-.H- l he green chlorophyll i-, limited 1" > eriain 

 portion- of ihc plasma, the chiomatophorc-. The true A! 

 arc capable of sexual reproduction. They arc all nioi ..... ' 

 adapted to an aquatic life. Many of them live in symhi" 

 some are true pai.i-i|. 



Wiil.ln.T. Akad. 'i. Wiuen* hafl n' 1878 



