ad 
Ser. CHLOROSPERME&. Fam. Oseillatorica. 
Piate CCCXLIT. 
CALOTHRIX LUTEOLA, Grev. 
Gen. Cuar. Filaments destitute of a mucous layer, erect, tufted or ag- 
gregated, fixed at the base, somewhat rigid, not oscillating. Zude 
continuous ; endochrome green, densely annulated, at length dissolved 
into lenticular sporidia. CatorHrix (4y.),—from xaos, Leautiful, 
and @pé, a hair. 
Carornrix Juteola ; filaments scattered, exceedingly minute and slender, 
filiform, flexible, obtuse, hyaline and pale yellowish, or containing an 
opake light green, interrupted, faintly annulated endochrome. 
CaLoruRix luteola, Grev. Crypt. Fl.t.299. Harv. in Hook. Br. L1. vol. il. 
p: 367. Harv. Man. ed. 1. p.157. ed. 2. p. 224. 
CaLOTHRIX melaleuca, Carm. Alg. Appin. MSS. 
LEIBLernta luteola, Avitz. Sp. Alg. p. 276. 
Has. On marine, filiform Alg, in tide-pools. Appin, Capt. Carmichael. 
Grocer. Distr. ? Helgoland, Kitz. 
Descr. Filaments of microscopic size, visible to the eye as a minute byssoid 
coating to small Alge, when seen under water, but invisible when the af- 
fected plant is lifted into the air; scattered, each thread standing apart, of 
equal diameter throughout, obtuse, very slender, flexible, quite simple, 
either, hyaline and pale yellowish, or more or less filled with an opake, an- 
nulated, light-green mass. The whole plant is so minute that it requires 
the highest powers of a compound microscope to make out its structure. 
DR ns nnn 
Our figure has unfortunately been printed in too green an 
ink, and is less characteristic than I could wish; and will not 
bear a favourable comparison with the beautiful figure given by 
Dr. Greville. In one respect, however, I am unable to sce this 
microscopic plant either as Dr. Greville or as Capt. Carmichael 
has described it, and yet we have all three had the same spe- 
cimens before us. By Carmichael, its discoverer, it is thus de- 
scribed :— Fi/aments in small tufts, a line or two in length, 
exceedingly slender, tortuous, tapering, of @ snow-white colour, 
and so opake as to appear intensely black when viewed against 
