CHLAMYDOCOCCUS. 165 



memoir, filling 160 pages in the Nova Acta Acad. Caes. 

 Leop. Carol. Nat. Cur. Vol. XXII r P. II, to which the 

 student is referred for the full, original details. Transla- 

 tions may be seen in A. Braun's Rejuvenescence, pp. 206-214, 

 and "Memoirs," by the Ray Society, 1853. Dr. Colin ex- 

 presses surprise that so simple a form should have evoked 

 so many different views. Almost every botanist who made 

 the plant a study suggested a new generic name. It is found 

 in the writings of different specialists under the following 

 terms, Chlamydomonas, Astasia, Gyges, Disceraea, Proto- 

 coccus, Gtoiococcus, Haematococcus, Palmella, Sphaerella, 

 Microcystis, Uredo, Torufa, Dematium, Byssus, and Lepraria. 

 It would not be in accord with the design of the present 

 work to enter upon lengthy details of the life-history of the 

 plant under consideration, but for illustrating a few of the 

 many forms a plant may assume in the round of its devel-: 

 opment, we copy some of Cohn's illustrations, and add very 

 brief explanations. After a contemplation of these figures, 

 the diversified ideas expressed by the many generic names 

 as above applied to this plant may not seem so strange. 



Plate CLIII, figs. 11-26, cells of resting forms of CM. pluvi- 

 alis; figs. 11, 12, two cells, carmine red, as they appear after 

 being dried for some time ; fig. 13, a large cell, lighter red 

 around the margins with a light central spot ; fig. 14, a cell 

 similar to last gradually changing to green with a light cen- 

 tral spot; fig. 15, cell chlorophyl green, with illuminated 

 spot surrounded by a halo of red ; fig. 16, a reddish brown 

 cell, with the middle changing to green, membrane thin ; 

 fig. 17, a cell kept for six years in a dried state, restored 

 with moisture ; it divides, one-half being green, the other 

 half reddish brown ; fig. 18, cell red, changes its form pre- 

 paratory to division ; fig. 19, division progressing ; fig. 20, 

 the same cell divided. The two daughter cells have a thin 

 membrane each, and still enclosed in the maternal mem- 

 brane ; fig. 21, cells divided a second time, producing four, 

 partially green cells ; fig. 22, a cell divided at once into four 

 spherical brown cells, somewhat motile in the maternal 

 membrane ; fig. 23, similar to fig. 22, showing only three 

 cells ; fig. 24, resting cell red and green within a wide color- 

 less envelope ; fig. 25, a green cell, red in the center, at the 

 point of changing into a mobile body ; fig. 26, another cell 

 like the last, with light green margins, middle red, prepar- 

 ing for mobility ; figs. 27-29, zoospores without envelope, 

 green ; figs. 30-32, three forms of zoospores, each enclosed 

 in a wide membranous envelope ; fig. 33, commencement of 



