Ser. CHLOROSPERMEX. Fam. Oscillatoriee. 
Puate CCXLIX. 
MICROCOLEUS ANGUIFORMIS, Harv. 
Gen. Cuar. Fidaments minute, rigid, straight, transversely striate, bundled, 
and enclosed within membranaceous, simple or branching ‘sheaths, 
from whose apices they oscillate. Mrcrocotnus (Desmaz.),— from 
puxpos, small, and kodeos, a sheath. 
Microcotegus anguiformis ; sheaths snake-like, simple, decumbent, tapering 
much to the extremity ; filaments slender, with distant strie. 
Microcotevs anguiformis, Harv. MSS. Hass. Fr. Water Alg. p. 261. 
t. 70. fig. 1. 
Has. Pools of brackish water, near the shore, at Dolgelly, Mr. Raé/s. 
Groar. Distr. Coast of Wales. 
Descr. This minute plant forms a dense stratum of a dark green colour on the 
surface of the mud. The sheaths are grouped together without order, de- 
cumbent, much entangled, and variously twisted into many snake-like folds, 
broad at the extremity from which the filaments oscillate, and tapering 
much towards the other end. The inclosed filaments are short, slender, 
and straight, with distant striae. The colour is a dull blackish green, 
without gloss when dry. 
OIL III een 
A minute but curious Alga, allied in many points to Oscilla- 
forta, from which genus Microcoleus chiefly differs in possessing 
frond-like sheaths, contaming threads bundled together. At 
first these sheaths appear scarcely more compound than a single 
filament, but as the plant advances, the sheath widens and is 
found full of a multitude of filaments. These oscillate, like 
those of an Oscillatoria, either from the wide mouth of the 
sheath, or from any accidental rupture which may happen in 
its side. 
I am indebted to Mr. Ralfs for the only specimens I have seen 
of this plant, and am not aware of any habitat for it, save the 
one above recorded. It ought to occur in similar places, on 
