282 NEMATOGENEZ. 
Gloiotrichia pisum. Thur. Ann. des Sci. Nat.1875, 377. - 
Of the size and form of a pea, sometimesas large as acherry, 
soft, even, or a little warted, dark olive-green, or brownish, tri- 
chomes elongated; the lower part blue-green, distinctly articu- 
lated, the upper part setiform, colourless, and indistinctly arti- 
culated, lower joints about equal in length and breadth, here 
and there somewhat swollen; heterocysts globose or subglobose. 
Size. Trichomes ‘01-012 mm. diam. at base. Spores -01- 
‘012 mm. diam., of variable length. 
Kirch. Alg. Schles. 222. 
Rivularia pisum, Ag. Syst., p. 25. Rabh. Alg. Hur. i, 206. 
Berk. Glean. t. 11, f.2. Emg. Fl. v., 392. Harv. Man. 150. 
Mack. Hib. 235. 
Linkia dura, Grev. Fl. Ed. 822. Johnst. Fl. Berw. ii., 261. 
Physactis pisum, Kutz. Tab. Phye. ii., t. 60, f. 3. 
In ponds, ditches, &c., adhering to aquatic plants. 
Plate XCVI. fig. 2. a, plants natural size; 5, trichomes of the same 
x 400 diam. 
Crass III. RHODOPHYCEZ (or Froripez). 
Multicellular Algex, with terminal vegetation. Thallus com- 
posed of aseries of cells, either singly or disposed in strata, 
which are naked or corticate, of variable form, membranaceous, 
crustaceous, filamentose, vertically branched, fasciculate, folia- 
ceous, &c. Cell contents for the most part reddish, rarely 
otherwise coloured. Reproductive organs of three kinds, very 
often disposed in different plants, viz. (1) Male organs, or an- 
theridia ; (2), Female organs, or cystocarps ; and (8), Tetra- 
sporangia. 
For the most part marine. 
Famity I. PORPHYRACEA. 
Thallus mucous-membranaceous, foliaceous or filamentose, 
formed from a single stratum of cells, chiefly purplish. Vege- 
tation by division of cells in two or more directions. Propaga- 
tion by tetraspores. 
Genus 117. BANGIA. Lyngb. (1819.) 
Thallus filamentous, terete or flattened, nearly plane, simple 
or branched; for the most part purplish, lubricose, formed from 
a single series of cells. Cell membrane thick, colourless, some- 
times lamellose. Multiplication by the repeated division of the 
cell-contents in all directions. 
