14 F. E. FRITSCH. 
Forma minor (Pl. L, fig. 27). 
Cellulis multo minoribus, 7-8 p latis, exacte globosis vel modice anguloso-globosis 
e mutua pressione, in familiis parvis cellularum eequalium agegregatis intra stratum 
Phormidii nidulantibus; membrana cellule eodem modo quo in typo incrassata ; 
chromatophora cum pyrenoide. 
This form gives rise to one-layered strata of circular or somewhat polygonal cells 
of almost uniform size. This going hand in hand with the small dimensions of the 
cells gives the strata a very characteristic regular appearance, in marked contrast to 
the generally non-uniform strata of the larger-celled type. The cell-membrane is 
prominently thickened to the same relative extent as in the larger forms, and the 
cells have a conspicuous pyrenoid. 
Forma robusta W. and G. 8. West, op. cit., p. 276, Pl. XXIV., figs. 52-54. 
(Pl. L., figs. 34-35). 
Cellulis majoribus vel multo majoribus, 35-78-100 yw latis, globosis vel distincte 
ellipsoideis, intra stratum Myxophycearum nidulantibus, solitariis vel saepe dense 
ageregatis ; membr. cell. 2°5-6 crassa et lamellosa; chromatophora saepe distincte 
parietali, globulis oleariis nullis vel magnis et conspicuis. 
The cells of this form attain immense dimensions and, although ordinarily 
spherical, as the Wests’ figures show them, are sometimes ellipsoidal (figs. 34, 35). In 
my material the cells of this form generally contained large and conspicuous 
oil-globules between the membrane and the contents. A pyrenoid does not appear 
to occur. Occasionally the cell-contents are reddish-brown (cf. above). The outer 
surface of the wall is frequently somewhat irregular, giving the appearance of flakes 
of membrane becoming detached. 
Forma jilamentosa (PI. L, fig. 28). 
Cellulis globosis vel modice depresso-globosis, 14—20 ys latis, in filamentis brevibus 
dispositis, intra stratum Myxophycearum nidulantibus, cum pyrenoidibus conspicuis. 
This form is rare. 
Forma simplea (PI. I., figs. 30, 31, 33). 
Cellulis globosis, 18-35 mw latis, solitariis vel in familiis ageregatis, intra stratum 
Myxophycearum nidulantibus vel libere natantibus, sine pyrenoidibus, sed cum granulis 
amylaceis multis. 
- This is the form originally described by Messrs. W. and G. 8. West. The form 
with small pyrenoids shown in fig. 32 connects f. simplex with f. typica. 
Forma stellata (PI. L, fig. 29). 
Cellulis clobosis, ut in forma typica, saepe ca. 30, latis, cum elobulis oleartis 
Ss 5) ? 5 
conspicuis, radiatim circum cytoplasma cellularum dispositis. 
