of Sphaeroplea annulina. 83 



in the closest relation to chlorophyll, and is equally produced 

 from this aud transformed into it. In normal conditions this 

 oil is diffused so minutely in the colourless plasma, forming a 

 kind of emulsion, that it appears in infinitely small, red globules 

 which might be confounded with the so-called protoplasm- 

 granules ; their oily nature may be ascertained, however, when 

 the spores die or are destroyed by chemical reagents, as the red 

 globules then become confluent into large red-lead-coloured 

 drops, strongly refracting light, soluble in aether, are coloured 

 bluish-green by iodine, and by a somewhat longer action of sul- 

 phuric acid acquire a blue colour; this last i-eaction exactly 

 resembles that of sulphuric acid on chlorophyll ; hence it is not 

 improbable that the acid converts the oil into the related sub- 

 stance chlorophyll. If the sulphuric acid remains long in con- 

 tact with the spores, the latter become bleached; the action of 

 light produces the same effect upon the spores when dead. The 

 red colouring matter of the spores of Sph(eroj)lca is different 

 from the eiythrophyll of leaves and flowers, but it occurs in the 

 spores of Bulbochate, as shown by Pringsheim, in Frotococcus 

 nivalis and pluvialis, Chroolepus lolithus, and many other Algfc, 

 also in Kmjlena sanguinea ; in every case it is changed, in the 

 course of development, into green chlorophyll, and vice versa. 

 The spores of Sphceroplea present a remarkable resemblance to 

 the red, stellate reproductive bodies which Ehrenberg pointed 

 out in the genus Volvox ( F. stellatus), and which, according to 

 my investigations, contain both red oil and starch-granules. 



The course of development of Spharojdea being hitherto alto- 

 gether unknown, and in fact the germination of the resting- 

 spores of the Algse generally never having been observed, except 

 in the Conjugate and Vaucheria, I resolved to turn to account an 

 immense mass of Spharoplea-siiores at my disposal, in an inves- 

 tigation, and accordingly, at the beginning of October 1854, I 

 jjlaced a portion of the red felted mass in a vessel of water. A 

 putrefaction immediately took place, through which the cells of 

 the fllaments were dissolved ; while the spores thus set free, — 

 which, as a microscopic examination sliowed, protected by their 

 two membranes, underwent no alteration whatever, — subsided to 

 the bottom of the vessel in countless numbers as a reddish mud. 

 Notwithstanding that the glass now stood all through the winter 

 in the window of a warm room, I could not detect any change 

 in the spores before March ; the germination showed itself first 

 after a few mild spring days, and it occurred simultaneously in 

 two separate vessels. In order to ascertain whether a six-months* 

 rest was actually necessary to the Sp/ici'roplea-s])OVCs, I jjlaccd a 

 fresh portion of the filamentous mass in water, at the end of 

 March ; in this case I observed germinating plants five days 



