27 
C. sphericum, Ney. De Toni’s description is:—‘ Coenobia 
* globose, or globose inclining to ovate, measuring as much as 90 in 
diameter, composed of 20 to 40 cells; cells almost hexagonal in 
circumference, prolonged outwards conically ; generally 15 » broad, 
spaces between the cells regular with 5-6 angles.” 
Cc. sphericum, (Veg.) var. compacta, Moebius (n. var.). 
Prof. Moebius says:—‘ This form differs from the typical one in this 
respect, that the cells are less considerably prolonged outwards and 
form smaller triangular or quadrangular spaces between them (Fig. 19). 
The colonies are spherical, 30-40 thick; the cells with envelopes about 
| lpthick; the number of cells in a colony seem to amount to 16-82. 
. The typical form is known in Europe, Argentine, Siberia, New 
Zealand.” Prof. Moebius then adds the following Latin description :— 
Australie (Burpengary).” (Colonies globose, 30-40 thick, composed 
ot irom 16 to 32 cells, about 15 » thick, which are less papillate than 
mn the typical form, and form smaller triangular or quadrangular 
tntereellular spaces.) 
ab. : Burpengary, Thos. L. Bancroft. 
PEDIASTRUM, Meyen. ae 
Cenobium plane, frond-like, discoid, or stellate, free swimming, 
formed of cells in a single, rarely in the centre in a double stratum, 
of the periphery entire or two-lobed, the lobes wedge-shaped, either 
single or two-toothed, sometimes elongated into a horn  Cell-contents 
( n, homogeneous at first, then granular.—-Rabh. Alg. Eur. iii., 69; 
ooke’s British Freshwater Alge. 
a tetras, (Kir. in 
* ioe Freshwater Alge). Ccenobium orbicular or oblong, perfectly 
thaped, deeply-lobed and arranged in the form of a cross; cells of the 
Brent cuneate, truncate at the base, deeply bilobate ; sinus narrow, 
+ *zelled eeenobia are often to be met with, mixed with desmids 
aC 
3 : OOK, 1.c. 
cen bie 19 bis: a, 4-celled ccenobia; 3, 8-celled ccenobia ; ¢, 8-celled 
24 Tum of unusual form, after Ralfs. 
: b. : Ponds, Thompson Estate, W. J. Byram. 
¢ _ : 
oo Ors ells fusiform or cylindrical, generally very gradually euspidate 
xg ea at the ends, rarely obtuse, straight or variously curv 
a seminate, or fasciculately aggregate, decussate in the centre 
Cells aely conjoined, rarely too laterally united at the end, “ge 
_ Divisions of the cells only in one direction.—Cooke’s 
ater Alge. : 
