\i i>< >t \ km I \i. :;| 



S. spinulosis ? Delp. Plate IV. fig. 14. 



Another variety of which I found only a single specimen, 

 in a pond, known as Chain Dam, Northampton Co., Pennsyl- 

 vania. It is not the same, Kiit near Delponte's described form. 

 1 1 needs verification. 

 I h'ameter 1 () u. 



S. i:i;< tangul \i:k. Wolle. Plate X LI X. fig. 9. 



Filament wide; cells twice ;i~ wide as long, deeply con- 

 stricted in the middle; serai-cells somewhal tapering near the 

 ends, producing acute-angled sinuses between the cells, and 

 between the semi-cells; ends truncate concave. Membrane 

 smooth. 



Diameter 5055 .; thickuess 1820 u. 



This form ia recorded with hesitation; it was one of the 

 latest finds in the fall of 1883; the specimens were limited, 



bul appeared to be in g 1 condition, lnt for bo much of ;i 



novelty, corroborative mens are needed. 



mm, MESOTAENIUM, Naeg. 

 Palmogloea, Kg. Plate III. figs. 515. 



( 'ells straight, shorl cylindrical, or oval, ends rounded, nol con- 

 stricted in the middle. Chlorophyl lamina axillary, sometimes 

 divided in the middle. 



I 'opulation takes place by two cells uniting side by side, the 

 contents flow ing t< igether. 



Kirchner remarks thai copulation in this genus is a simple union 

 of two cells, leaving no husks or remains of empty cells; (compare 



figs. 5 9). This process accords with my observations, bul \V I 



illustrates another mode transferred in figs. 1315, in which the 

 contents of the cells ri<>w together and arc surrounded by a new 

 membrane ; in this case the remain- of the old cells are present. 



These plant- occur frequently in small pools, on dripping rocks, 

 damp walls, wet ground and the like; sometimes singly but more 

 frequently associated in families in a gelatinous mucus. 



M. Braunii, I >. By. {Palmogloea macrococca, Kg.) Plate III, 

 figs. 59. 







Cells cylindrical, 2-2| times longer than wide, .nil- flatly 



