98 
NEW BRITISH FRESH-WATER ALGJS. 
Nostoc hyalinum, Bennett in Journ. Roy. Micr. Soc. 1886, p. 4, t. 1. 
f. 2, 3. 
Free swimming, very minute. Gelatinous envelope globose or 
slightly ellipsoidal, 0’21 mm. in diameter, lamellose, perfectly 
colourless and transparent. Trichorqe single in each envelope, in- 
terwoven. Cells ellipsoidal or nearly globose, green, bp in dia- 
meter (about forty to the length of the envelope). Heterocysts 
intercalary, very few in number, three to four in each envelope, 
spherical, green, 6-7 p in diameter. 
In a bog pool. Loughrigg Fell. 
[It is difficult to recognise any substantial specific difference 
between this and N. minutissimum , Kutz.]. 
Pediastrum compactum, Bennett Journ. Boy. Micr. Soc. 1886, p. 5, 
t. 1,/. 4, 5. 
Ceenobium oval and perfectly regular, -(LC^-’O-IG mm. in length 
(or probably more), rather more than half as broad as long. Peri- 
phery composed of 32 lunate cells (in the smaller specimens) with 
two somewhat divergent, very slender, tapering, not bidentate horns, 
quite as long as the cells themselves. Inner cells irregularly poly- 
gonal and densely packed, without any lacunse, in 2-4 rows. Cae- 
nobium invested with a distinct gelatinous envelope. Endochrome 
vellow-green, that of peripheral cells of a deeper colour, which 
gives the appearance ^n.'nder a low power, of a deep green border. 
Length of cells about 6p. 
Bog pools.. Loughrigg. 
Mesocarpus ? neaumensis, Bennett Journ. Micr. Soc. 1886, p. 15, t. 2 
/. 31, 32. 
Sterile cells, 25 p long by 20-25 p broad. Endochrome in a single 
axile plate, with one row of large starch corpuscles, and numerous 
smaller ones. Conjugation lateral, between two adjacent cells. 
Fertile cells somewhat ventricose, 200 p long by 50 p broad at the 
widest part, connected with the adjoining empty cell by an elbow 
50 p broad, across which the dividing septum reaches only about 
half way. Zygosperm oval, 90 p by 4 Op, always nearer to the end 
of the cell where conjugation has taken place ; cell wall of zygo- 
sperm quite smooth. 
In a duck- pond. Neaum Crag, Skelwith Bridge. 
Zygnema Hassallii, Bennett , l. c. 
We have to thank Mr. Bennett for reminding us that Zygnema 
anomalum , Cooke “ Fresh Water Algae,” is not the Zygnema ano- 
malum, Kutzing, and therefore he substitutes the above name, 
which we do not accept. Kutzing’s species was subsequent to 
Hassall’s, was supposed by Kutzing to be the same as Hassall’s 
species, and when we pointed out that it was not, it was our im- 
pression that it was Kutzing’s specific name that should be changed 
(as it originated in an error of Kutzing) and not that of the true 
original Z. anomalum. To this we shall adhere, and recommend 
that the continental species shall abandon the name in favour of 
