138 SIPHOPHYCEA, 
Size. Threads :006--012 mm. diam. 
Rabh. Alg. Eur. iii., 323. Kutz. Tab. iii, t. 44, f. 1, 2. 
Eng. Fl. v.,p. 351. Eng. Bot. ii, p.159. Harv. Man. 126. 
Mack. Hib. 224. Kirsch. Alg. Schl. p. 79. 
Conferva sordida, Dillw. Conf., t. 60. Johnst. Fl. Berw. ii., 
254. Eng. Bot. i, t. 2303. Grev. Fl. Ed. 317. Gray Arr. 
i., 310. 
Vesiculifera bombycina, Jenner Fl. Tunb. Wells, 186. 
In ditches, pools, &c., common. 
Plate LIII. fig. 4. Portions of threads of C. bombycina X 400. 
Genus 60. CH.ETOMORPHA. Kutz. (1845.) 
Articulate thread simple, nearly equally thick, fixed by a 
discoid, or root-like divided base, lower articulations always 
short, before division equal, or half as long again as the diameter, 
after division shorter than the diameter, upper articulations more 
or less elongated. Cell-membrane thick, firm, sub-cartilagi- 
nous, manifestly lamellose. Cell contents green, becoming by 
age parietal, continuous, finely granulate, containing a few 
starch granules. 
Propagation by zoogonidia. 
Chiefly marine, a few in brackish water. 
The lamination of the cell walls in this genus, and in Cladophora, 
appeared to Braun to present some analogy to the rings in vascular 
stems. He says, ‘The great number of layers which may be distin- 
guished by suitable treatment in the cell membrane, even of plants of 
short life (Cladophora, Botrydium, &c.), is not opposed to the assump- 
tion that they are diurnal layers, and it is imaginable, under this 
hypothesis, that bright and dull days, as well as the age of the cell, and 
other circumstances, may effect important modifications in reference to 
the formation of distinguishable layers.” 
Chetomorpha litorea. (Harv.) 
Rigid, green, crispate ; articulations before division one and 
a-half times as long as the diameter, here and there swollen in 
pairs and discoloured. 
Size. Threads‘16 mm. diam. 
Rabh. Alg. Eur. iii., 327. 
Conferva litorea, Harv. Man. p. 208. Phyc. Britt., t. 333. 
Conferva linum, Harv. in Eng. FI. v., 352. Wyatt, Alg. 
Danm., No. 220. 
In salt water ditches, and estuaries. 
“Filaments 3-4 inches long or more, loosely bundled together in 
prostrate or floating strata of considerable extent, and of a pale green © 
colour, becoming darker and duller asthe season advances. Each fila- 
ment is irregularly curled and twisted, and sometimes angularly bent. 
The articulations are cylindrical, filled with a pale green watery endo- 
