356 THE BOTANICAL MAGAZINE. LVoi. xxx. No. 3oj. 



The attractive power of the CO., and phosphoric acid has been 

 demonstrated by Frank*^ in Chlamydotnonas tingens. 



In this connection it ma}- be interesting to note, that it re- 

 sponds even to those acids, which act upon the organism as 

 the toxic agents as for instance osmic acid, picric acid, etc. 

 In those cases the organism became inactive or was killed in 

 the capillary or at its mouth. 



Finalh' the morphological accounts of the present Chlamy- 

 dotnonas are to be given (Figs. 5-8). 



The swarmspores are oval or sometimes round in shape. 

 The cell wall becomes, when the culture gets old, generally very 

 thick at the posterior part of the body, in a manner to give the 

 latter a crescent shape (Fig. 6). At the anterior pole the cell 

 wall forms a ])apilla or a little thickening. Through this 

 thickening of the membrane two long cilia are protruded from 

 the protoplast, which is rather roundish at that region. Near 

 the base of the cilia two contractile vacuoles are found. The 

 eye-spot is situated at the anterior one third region of the 

 body. It is large and rod-shaped with its pointed end towards 

 the anterior pole. In this eye-spot many small red pigments 

 are found. It is noted here that the eye-spot is sometimes very 

 bright and clear, and sometimes pale and obscure. The chro- 

 matophore is of the shape of a bottle and its bottom is thick 

 and biconvex. The p\a-enoid is also biconvex along its major 

 axis, but round in the section of the minor axis. It is situated 

 near the inner or upper boundary' of the bottom of the chromato- 

 phore. On treating w^ith potassium iodide iodine, the reddish 

 brown " starch " grains are found in the pyrenoid as well as 

 free in the chromatophore (Fig. 7). They are large and arranged 

 in a certain order in the former, small and scattered in the 

 latter. In the cytoplasm otherwise many drops of oil are found 

 which exhibit beutiful oil reactions with sudan III and !"/„ aqu. 

 solution of osmium tetraoxide. They are especially abundant 

 in the non-motile form (Fig. 8). The nucleus is not visible in 



1) Bot. Ztg. Bd. 62. 1904. 



2) Compare TFEFFJai, AV., l.o. I. 1884. !>. 338, Pfkffkr, \V., I.e. 1. 1888. j). 

 628, ;uid Shibata, K., Jalirb. f. wis.s. Bot. XLIX. lUll. 



