ZOOLOQY AND BOTANY, MICROSCOPY, ETC. 99 



of some higher organism enveloped in a coat of mucilage, as is the 

 case with detached cells of Draparnaldia, the resting condition of 

 Clilamydomonas, &c. 



In gelatinous masses fresh collected from rocks, moss, &c., Richter 

 found, mingled with Gloeocystis rupestris, pale, star-shaped, and again 

 green spherical spined cells with a firm cell- wall, from 8 to 10 ^ in 

 diameter, which he regards, with some hesitation, as its resting-spores. 

 He considers also Gloeocapsa monococca and stillicidiorum Ktz. rightly 

 to belong to the same cycle of development as Gloeocystis vesiculosa, and 

 Palmogloea lurida and rupestris to belong to G. rupestris. 



The contents of young active cells is uniformly distributed through 

 the cell-cavity, and is finely granular ; or is sometimes accumulated 

 on one side of the cell, the other half containing only a pale bluish 

 protoplasm. The cells are elliptical, often somewhat pointed at one 

 end, varying in length from 7 to 12 /z, and in breadth from 4 to 8 yu,. 

 The cell is usually surrounded by a cylindrical envelope of jelly ; but" 

 this is often so delicate as only to be detected when dry. In other 

 examples again, the chlorophyll occupies only one- half of the cell- 

 cavity, and is bounded by a diagonal line. In others, the chlorophyll- 

 mass has somewhat the form of a horseshoe or kidney. 



In individuals in which the contents are evenly distributed, and 

 which are also somewhat swollen, a division takes place into four 

 roundish or elliptical parietal balls, which soon develop into elongated 

 ovoid bodies and fill up the entire cavity. Usually the common 

 envelope then bursts, and the daughter-cells escape and go through 

 the same process again ; or the envelope expands into a spherical or 

 cylindrical form, till it has reached 17, 19, or even 30 /a in length, 

 enclosing two generations of daughter-cells. The daughter-cells do 

 not always acquire special gelatinous envelopes, but sometimes lie free 

 in the common envelope. Sometimes there appears what looks like 

 an arrested production of swarm-spores. 



The cylindrical form is identified by the author with Gloeocapsa 

 monococca Ktz. ; the subsequent division and formation of daughter- 

 cells within the common envelope results in the production of Gloeo- 

 cystis vesiculosa Naeg. This sometimes assumes a Palmella-condition, 

 and is then Gloeocapsa stillicidiorum Ktz. The formation of special 

 envelopes ceases, the daughter-cells lie free in the common envelope, 

 and divide repeatedly in tetrahedra, thus forming mulberry-like 

 colonies, the common envelope having by this time deliquesced. The 

 separate finally spherical cells vary greatly in size ; they were 

 measured between 3 and 7 /a in diameter. From these again at length 

 the Gloeocystis-fovm was developed, special vesicles assuming again a 

 cylindrical form. In this generation the author noticed a process 

 which might be a rudimentary and uncompleted act of conjugation. 



According to these observations, therefore, Gloeocystis has a form 

 of development consisting of cylindrical cells, which may be encysted 

 or free, and which alternate with the familiar spherical encysted form ; 

 a palmella condition with tetrahedral divisions occurring also within 

 the latter. The first form may be termed the Cylindrocystis condition. 

 Each of these forms may be developed from another ; and Gloeocapsa, 



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