FRESH-WATER ALG.E OF THE UNITED STATES. 125 



adjoining ends of the next joint being similar, these projections being produced by an annular 

 grooved rim. L. "**" GOO", li. T iW' rWi"- (Archer) 



Genus BAMBUS1NA. 



Cellule oblongo-orculiformes, in filamonta articulata nodosa dense conjunct, medio vittu trans- 

 VIT-:I nirinis duiilws annulifnriniluis liniitiita instructs, itaque superue et infcrue bideutaUe, fronte 

 circulurt'.s, supra et infru (lento union proiuiuente. (R.) 



Cells oblong-orculiforiu, densely united into an articulate nodoso filament, surrounded by two 

 median bonds. 



II. IIr l>i.-oiiii, KTZ. 



li. lilumriitis njjdoso-articulatis ; cellulis diametro duplo long! ori bus. (R.) 



Diam. 0.00077" 0.00092". (R.) 



Syn. B. Brtbissanii, KUTZINO. RABENHOBBT, Flora Europ., Algarnm, Sect III. p. 152. 



Uab. South Carolina. (Ravenel) Wood. South Carolina; Georgia ; Florida ; Rhode Island. 

 Bailey. 



(Didymopriura Borreri, (Ralfs)) Joints inflated, barrel-shaped, longer than broad, without a 

 thiokened border at their junction; angles bicrenate, crenatures rounded; transverse view 

 circular; sporangium elliptic, formed within the (for some time) persistent extensions from 

 the conjugating joints, which do not previously break np into single joints, but couple, still 

 united in the filament, in a confused or zigzag manner, some of the joints remaining unchanged. 

 L. j4 ff ". B. T^". 



Remarks. The specimens which I have seen agree well with the descriptions, 

 :t in regard to size; some of the cells which I measured were more than 

 T^Vff f an i uc k in di ame ter. 



Genus DIDYMOPRIUM. 



Cellnlte oblongo-ellipticse, modice compressse, ancipitcs, angulis porrcctis inciso-bidentatis, in fila- 

 menta articulata biconvexa et torts sine istluuo arete conjunctsc, et in vagina murosa indusie. 

 ' plasma cbloropbyllosa cellulse a fronte cruciatim disposita, cujus crura e lamiuis duabus paric- 

 talibus divergentibns granum amylaceum uuicum involventibus formantur. 



Cells oblong-elliptical, moderately compressed, two-edged, with the produced angles inciscly-biden- 

 tate, closely united into a biconvex and twisted filament, which is inclosed in a mucoid sheath, cytio- 

 plasm so placed as to be cruciate when viewed from the front (end), each crus composed of two 

 parietal divergent lamina, each of which contains a single starch granule. 



D. Grevillii, KTZ. 



D. cellulis oblongis diametro duplo brevioribus, saturate viridibus. (R.) 

 Dwm.0.0024" 0.0031." (R.) 



Syn. D. Orevillii, KVTZIXO. RABKNHORST, Flora Europ. Algarnm, Sect. III. p. 153. 

 Sab. Georgia, South Carolina ; Bailey. Pennsylvania ; Wood. 



Sheath distinct ; joints broader than long, with a thickened border at their junction ; angles 

 bidentate ; teeth angular; transverse view broadly elliptic. Sporangium orbicular, formed 

 within one of the two conjugating joints, the endochrome passing over from one by a narrow 

 connecting tube produced between the otherwise, but little altered, broken-up single joints. (A.) 



Remark. Fig. 13, pi. 12, represents the end view of a broken filament of this 

 species. 



