276 NEMATOGENE. 
Calothrix Orsiniana. Thur. Ann. Sci. Nat. 
Forming a pulvinate stratum, as much as two lines in thick- 
ness, dark brown, lubricous, opaque; trichomes elongated, 
branched, of nearly equal thickness, cuspidate at the apex or 
obtuse, distinctly articulate, here and there moniliform ; sheaths 
thick, lamellose, golden brown, from the base to above the 
middle even, apical portion more or less dividing in fibrous 
lamelle. 
Sizz. Trichomes with sheath -01-012 mm., without sheath 
“004-006 mm. 
Kirch. Alg. Schles., p. 219. 
Scytonoma cirrhosum, Berk. Eng. Bot. ii., t. 2920. 
Cenocoleus cirrhosus, Berk. Eng. Bot. ii., sub. t. 2940. 
Schizosiphon cataracte. Nag. in Kutz. Tab. Phye. ii., t. 52, 
f.1. Rab. Alg. Eur. ii., 235. 
On rocks and submerged stones. 
Although we have seen no authentic specimen of Berkeley’s Cenoco- 
leus, the specimens from Ben Lawers, which we have referred as above, 
appear to us to belong to the same species, as far as can be judged in the 
absence of al] measurement. 
Plate CXIII. fig. 1. Portion of trichome X 400; 4, small fragment 
magnified with sheath from Eng. Bot. t. 2920; ¢, cells of trichome free 
from the sheath. 
Calothrix Dillwyni. (Hass. Aig.) 
Flaccid, bluish green or brown, trichomes usually cohering in 
pairs, sheaths inconspicuous, except towards the base, joints 
about half as long as their diameter, heterocysts at the base of 
the branches ovate or cordate. 
Size. Trichomes :005--006 mm., with sheaths '008--01 mn. 
Desmonema Dillwynii, Berk. Eng. Bot. ii., Supp., t. 2958. 
Tolypothrix Dillwyni, Hass. Alg. 242, t. 68, f. 4-5. 
Microcoleus Dillwyni, Harv. Man. 169. 
Conferva vaginata, Dillw. Conf., t. 99. 
On mosses and moist rocks. 
Plant minute, flaccid, much branched, seldom a quarter of an inch in 
length, varying in colour from brown to bluish green. Filaments 
usually cobering in pairs. Sheaths inconspicuous, except those of rhe 
older filaments at the base of the plant, which‘ become thickened and of 
areddish brown colour. Endochrome annulated, more evidently so in 
the recently formed filaments than at the base of the plant, dotted from 
the presence of minute granules; joints about twice as broad as long, 
the terminal one somewhat dilated and hemispherical. The branches 
towards the base of the plant are seated each upon a connecting cell 
(heterocyst) of an ovate or cordate form. The plant possesses other 
branches formed by a dislocation of the endochrome, each separated 
portion becoming elongated, the lower portion towards the apex of the 
