Ser. CHLOROSPERME. Fam. Oscillatoriea. 
Puate CLX. 
SCHIZOTHRIX CRESSWELLII, Zar. 
Gen. Cuan. “ Filaments involved in a thick, lamellar sheath, rigid, curled, 
thickened at the base, at length longitudinally divided. Spermatia 
lateral.” Kitz. Scuizornrix (Kiitz.),—from oxo, to divide, and 
Opé, a hair: hair-splitter. 
Scuizorurix Cresswellii ; forming dense, soft, pulvimate, convex tufts ; 
filaments very slender, curved, fastigiate, collected into branching 
bundles. 
ScurzoruRix Cresswellii, Harv. in Herb. (1846.) 
CaLotTurix Cresswellii, Harv. Phyc. Brit. sub Tab. 76 in not. 
Has. On sandstone maritime rocks, near high-water mark, exposed to the 
drip of fresh water. Annual. Winter. Near the Picket rock, Sidmouth, 
Rev. R. Cresswell. 
Geogr. Distr. South coast of England. 
Descr. Spreading over the surface of soft sandstone rocks, in continuous, convex, 
roundish or oval patches, which run one into another, and cover the rock 
for spaces several inches in diameter, in a more or less regular manner. 
Patches or tufts one or two inches long, half an inch high (or thick), soft, 
somewhat slimy, composed of very slender, yellowish or greenish-olive, 
hyaline filaments, collected into dense, rope-like, branching bundles. 
Bundles fastigiate. Filaments exceedingly slender, once or twice divided 
in a dichotomous manner, apparently by a splitting of the original tube or 
cell. Substance soft, closely adhering to paper, but not glossy when dry. 
Colour, a greenish olive. 
In the remarks under Plate LXXYVI. of the first volume, 
I mentioned that I had received from the Rev. R. Cresswell of 
Salcombe Regis, what I regarded as a new species of Calothria, 
and proposed to dedicate it to him by the name Cresswellii. 
On communicating a specimen, shortly afterwards, to Professor 
Kiitzing, I was informed by that author that it belonged to his 
recently instituted genus Schizothrixv, of which it appeared to be 
a new and very distinct species. ‘This genus is closely related to 
Calothrix, from which it differs chiefly in the mode of increase of 
its filaments, which divide at maturity in a dichotomous manner. 
I am not very sure, however, that there may not be some 
optical delusion in this matter, and offer the third figure m_ the 
plate with some hesitation. In habit this plant bears considerable 
