328 Mr. J. Ralfs on the Nostochinez. 
p- 201. t. 68. fig. D (1819). Anabaina membranina, Bory, Arthr. 
fig. 7 d (according to Kiitzing) ; Mougeot et Nestler, Stirpes Cryp- 
togamiz Vogeso-Rhenaneze, no. 896. Anabena Flos-aque, Trevir. 
in Linn. 1843, t. 3. fig. 5—7 ; Kiitzing, Phycologia Generalis, p. 209; 
Phycologia Germaniea, p. 171 ; Species Algarum, p. 289. Sphero- 
zyga membranina, Endlicher, Mantissa Bot. Alterum Sup. tertium, 
p- 12 (1843). Trichormus incurvus, Allman, Annals of Nat. Hist. 
vol. xi. p. 163. t. 5 (1843) ; Hassall, Brit. Freshwater Algze, p. 285. 
t. yo.) 1. 
Stagnant pools and other still waters. Portmore Lough, Antrim, 
Mr.W.Thompson ; Ayrshire, Rev. D. Landsborough ; Dolgelley, J.R. ; 
Oswestry, Shropshire, Rev. T. Salwey ; Grand Canal Dock, Dublin, 
Professor Allman. 
Finland, Lyngbye ; France, Bory ; Germany, Kiitzing. 
Trichormus Flos-aque rises to the surface of the water in gela- 
tinous masses of considerable size, and is generally of a rich 
bluish green colour. Filaments curved and beautifully monili- 
form. Cells spherical; vesicular ones resembling the ordinary 
ones, but larger and without granular matter. Sporangia I have 
not detected, but since cells, not different in form from ordinary 
ones, are often filled with granular matter, there is probably no 
very obvious difference between the latter and the sporangia. 
Puate VIII. fig. 2. 
2. T. spiralis (Thompson). Filaments coiled or spiral ; ordinary cells 
subquadrate or orbicular ; vesicular cells and sporangia orbicular. 
Anabaina spiralis, Thompson in Annals and Mag. of Nat. Hist. 
vol. vy. p. 81 (1846). Sperillum Thompsoni, Hassall, Brit. Fresh- 
water Algz, p. 278. t. 75. fig. 7 (1845). 
Ballydrain Lake, near Belfast, Mr. Thompson; Petersfield, Mr. 
Jenner. 3 
I regret that the specimens Mr. Thompson has sent me are 
too imperfect to serve for the identification of the species. I am 
by no means certain that Mr. Jenner’s plant is identical with the 
Irish one, and I have referred it to this species in deference to 
the opinions of Mr. Thwaites and Mr. Jenner, rather than from 
my own conviction. 
The filament in Mr. Jenner’s specimen is somewhat coarse, and 
coiled rather than loosely spiral. The ordinary joimts are more 
or less quadrate, the vesicular cells orbieular, and the sporangia 
similar to the ordinary cells, but larger and more orbicular. 
Mr. Thompson’s figure represents his 7. spiralis with perfectly 
orbicular ordinary cells, and a slender filament which, except in 
being spiral, scarcely differs from Trichormus Flos-aque. 
Puate VIII. fig. 3. a, Mr. Jenner’s specimen; 0, fragment of Irish spe- 
cimen with sporangium between ordinary cells; ¢, mature sporangium. 
