GLOEOCAPSA. 33 1 



of forms of Sirosiphon; they have their origin in the filaments, 

 and again develop the same forms. Similar cells may occur also 

 in the development of plants of other genera, as tiw/tonema ; 

 (compare Plate CLXXXIV, fig. 41 ), but they appeal- specially 

 confined to Sirosiphon. 



In the process of development there are several modes, the 

 one more direct than the other. The former is shown on Plate 

 CXCV, figs. 5-9, also on Plate CXCIV, figs. 4-10 ; the other in- 

 volving the same principle yet more indirect. The microgonidia, 

 scattered by the decay of the membranes of the cells of the fila- 

 ments, begin to develop and soon present an appearance as 

 Plate CXCI, figs. 15, 16. These small, almost colorless cells, 

 grow and produce larger cells, with a single central nucleus 

 (fig. 17), which next divides and they appear with two nuclei or 

 cells ; these develop into the full-grown cells, (figs. 19, 20). 

 Plate OCX, figs. 26-31, illustrate more fully the advancing stages 

 of growth of Gloeocapm magma, (Breb.) Kg., from micro to 

 macrospores. We take these as good representative forms, to 

 serve to illustrate a few of the species (!) which have been re- 

 corded by various authors ; many differing only in color, which 

 in itself can not be taken as a characteristic feature. It is too 

 inconstant. A few of the forms of this genus may be quoted for 

 illustration, as follows : 



GLOEOCAPSA MAGMA, ( Breb. ) Kg. 



Forms a grumous thallus, purplish brown ; teguments 

 coppery brown, or brownish red ; central cell aeruginous. 



Plate CCX, figs. 26-31. 



GLOEOCAPSA POLYDERMATICA, Kg. 



Thallus gelatinous dirty green or olive, becoming brownish. 

 Tegument hyaline, lamellose. Cell (central) aeruginous. 



Plate COX, figs. 29-31, represent the features, not color. 



GLOEOCAPSA CORACINA, Kg. 



Thallus crustaceous, nearly black ; tegument very pale 

 violet, distinctly lamellose ; cell aeruginous. 



GLOEOCAPSA AERUGINOSA, ( Carni. ) Kg. 



Thallus crustaceous, glaucous green ; teguments thick 

 colorless, rather indistinctly lamellose ; cells aeruginous. 



Plate CCX, figs. 27, 28, differing in color from the others. 



