254 NEMATOGENE. 
in reality a Lyngbya, allied to L. estuarii, and not « true Oscillaria. 
We are indebted to Professor Percival Wright for an examination of 
authentic specimens of this, and several other of Harvey’s species. 
Plate XCVIILI jig. 4. Portion of trichome X 400. 
Doubtful Species. 
Oscillaria Dickiei (Hass.) Rabh. Alg. Eur. 11., 113. 
Stratum pale chesnut-brown, gelatinous, shining ; trichomes 
of medium size, long, straight, fragile, with visible spaces 
between the joints. 
Size. Not determined. 
Oscillatoria Dickiei, Hass. Alg. 258, t. 72, f. 18. 
Pools of fresh water near the sea. 
The colour of this species is so peculiar as at once to distinguish it 
from all others which bave been described. This colour is preserved in 
drying; the filaments are of nearly the same diameter with those of 
O. tenuis, but they preserve their calibre when dried.—Hassall. 
Oscillaria thermalis. (Hass.) Rabh. Alg. Eur. 11, 1138. 
Trichomes straight, rigid, fragile, green; divisions of the 
joints distinct, rather remote. 
Size. Not determined. 
Oscillatoria thermalis, Hass. Alg. 250, t. 72, f. 3. 
In warm water. 
The figures and descriptions in Hassall’s work are wholly insnfficient 
for the proper identification of this and the following species. 
Oscillaria virescens (Hass.) Rabh. Alg. Eur. 1., 113. 
Stratum pale blue-green ; trichomes of medium size, pale 
yellowish-green, with the joints rather distant, nearly equal in 
length to their diameter. 
Size. Not determined. 
Oscillatoria virescens, Hass. Alg. 250, t. 71, f. 9. 
On the ground. 
GENUS 102. MICROCOLEUS. Desm. (1823.) 
Trichomes rigid, articulate, crowded together in bundles, 
enclosed in a common mucous sheath, either closed or open at 
the apex; sheath ample, colourless, more or less lamellose, 
rarely indistinct. —= Chthonoblastus, Kutz. (1843.) 
