1881.J 



MICROSCOPICAL JOURNAL. 



27 



This alga, because of the circum- 

 stance that it assumes a steel blue 

 color from lack of sufficient moisture, 

 has been subjected to different sys- 

 tematic classifications. I have drawn 

 attention to this changing coloration 

 in Botan. Ccntralbl.^ No. 19, p. 605, and 

 endeavored to explain it, by showing 

 that the quantity of water influenced 

 the color. In Phykol. Generalis we 

 find it, p. 175, as Gloeocapsa with 

 gonidiis ceruginosis ; later in Spec. Al- 

 ga r., p. 229, as Palmoglxa monococca 

 i. ceruginosa. Nageli * considered it 

 as a Glxothece, and Rabenhorst fol- 

 lowed him in this conclusion {Flora 

 Europ. Alg., Vol. II, p. 62), and 

 Kirchner {Kryptogame?tfl. Sc/iles. ,Yo\. 

 .II, first half). 



The contents of the young cells in 

 the upper vegetation are evenly dis- 

 tributed within them, finely granular, 

 and there is a faintly defined, laterally 

 placed chlorophyll vesicle, which 

 sometimes seems to be absent. Or, 

 the contents are arranged on one side 

 of the celLs, in the line of the axis, and 

 form on one of the sides a conchoi- 

 dal body which fills one-half of the 

 cell up to a sharply defined limit, 

 while in the other half only bluish 

 protoplasm is to be seen. This group- 

 ing of the contents is characteristic. 

 The cells are elliptical, but in many 

 cases the end is somewhat pointed. 

 The length is variable, 7-12/", the 

 breadth 4-8/^. As a rule, the cells are 

 enveloped in a gelatinous coat, which 

 is often so delicate as to be only 

 visible in dried specimens. 



The cell contents are sometimes ar- 

 ranged in still another manner. The 

 chlorophyll is then found to be res- 

 tricted to half the cell, but the well-de- 

 fined border runs diagonally. It seem- 

 ed to me as though a shifting of the 

 chlorophyll took place. Again, the 

 chlorophyll may also be uniformly 

 distributed in a lateral, half circular 

 segment or clear stripe, which ex- 

 tends from the border to the middle, 

 so that the chlorophyll mass appears 

 more or less hor se-shoe or kidney- 



* Einzellige Algen, p. 52. 



shaped. Such chlorophyll grouping 

 is also found in Palmogxa rupestris, 

 lurida and micrococca drawn by Kiit- 

 zing in Tab. Fhyk., I, T. 25. I 

 would consider the latter, without 

 hesitation, as identical with Gloeocapsa 

 monococca, did not the statement of 

 Rabenhorst* about angular zygos- 

 pores oppose this view, for the fungus- 

 hypha, which spreads around the 

 envelope of P. micrococca likewise 

 appeared in this. 



In those individuals, the contents of 

 which were evenly distributed, and 

 which also were somewhat swollen, 

 there appeared, previous to division, 

 a separation into four spherical or 

 elliptical, peripheral balls, which soon 

 formed elongated egg-shaped bodies, 

 and occupied the entire cell, two 

 being in the line of the axis and two 

 at a right angle to these. Usually the 

 mother-cell bursts and the exit of the 

 daughter-cells follows, which in turn 

 continue this division ; or else the 

 mother-cell expands, assumes a sphe- 

 rical or cylindrical shape, with a 

 length of 17/^, 19/^ and 30/^, and en- 

 closes daughter-cells and later gene- 

 rations. A special gelatinous mem- 

 brane does not always appear for the 

 daughter-cells ; the latter then remain 

 free in the general mass of jelly. I 

 also observed cases in which the mo- 

 ther-cells divided into only two 

 daughter-cells, likewise placed in 

 the line of the axis, which by shifting 

 and at the same time extending the 

 envelope finally rested one behind 

 the other. This formation of daugh- 

 ter-cells takes place by free cell forma- 

 tion, and might be regarded as a 

 suppressed swarm-spore formation, 

 especially since I found, in later and 

 similarly shaped generations, a quad- 

 ruple division in which the short, 

 cylindrical daughter- cells all collected 

 together, parallel with the longitudinal 

 axis — a multiplication which took 

 place by repeated binary division 

 in one and the same direction, and 

 corresponded to a vegetative process. 

 One might easily be led to regard 



* Flora Eirop. Alg. Ill, p. Il6. 



