PROCEEDINGS OF SOCIETIES. 79 
Micrasterias oscitans (2a/f), rare. 
a crenata (Bred.), not wwcommon. 
5 truncata (Corda), 
Kuastrum verrucosum (H/r.), rare ; base of “Seechon” mouutain. 
5 crassum (Bred.), not uncommon. 
4 oblovgum (Grev.), common. 
A affine (Ra//s), not uncommon. 
3 ampullaceum ( ), rare. 
s didelta (Zurp.), Tete 
” ansatum (£.), 
A pectinatum (Bred. ys not rare. 
Sc rostratum (Ra/fs), rare. 
cf elegans a (Bred.), frequent. 
A, binale (Zurp.), not uncommon. 
sublobatum (Bred.), rare. 
Cosinarium cucumis (Corda), not common. 
3 pyramidatum (Bred.), 
: bioculatum (Bred.), © 
3 granatum (Greb.), rare. 
= Meneghinii (Bred.), not uncommon. 
- crenatum (Ra/fs), rare. 
ie tetraophthalmum (A‘wfz.), rare. 
3 botrytis (Bory), not uncommon. [I met with in the canal water 
a form, probably a variety of C. botrytis, which, like it, is 
rough with pearly granules, but differimg in having the deep 
constriction not forming a linear notch on each side in the 
front view; but wider at the outside, causing the angles at 
the base of the segments to be more rounded; the segments 
broadest at the hase, and gradually narrowing towards the 
abruptly truncate ends in a concave manner, thus somewhat 
pointing away from each other at the lower angles of each, 
while the angles at the ends are more acute and “defined than 
in C. botrytis. The end view is narrow elliptic. | 
Ae margaritiferum a and 6 (Turp.), frequent. 
S Brebissonii (Menegh.), not unfrequent. 
a celatum ( ), rare. 
i: eylindricum (Ra/fs), rare. 
a5 cucurbita (Bred.), B 
phaseolus (Bred.), 7 
Xanthidium armatum (Breb.), frequent. 
A aculeatum (Hhr.), not uncommon. 
c cristatum a and 6 (Bred.), rare. 
%y fasciculatum a (Hhr.), 
= octocorne a (Hhr.), frequent. [My opinion is that Xanthidium 
octocorne (var. a), so called, should more properly come under 
the genus Arthrodesmus, slightly extending the characters of 
the latter, so as to embrace the organism in question. 
Xanthidium appears a very natural genus; but 1. octocorne 
seems out of place in it. Its affinity to some forms of /r- 
throdesmus incus cannot but be apparent. I have met with 
both species mixed in abundance. | 
Arthrodesmus convergens (Z/r.), not uncommon. 
incus a and B (Breb.), not uncommon. 
Stantastrum dejectum, a, 8, and y (Bred.), frequent. 
3 cuspidatum (Bred.), not unfrequent. 
3 Dickiei (Ra/fs), rare. 
1 muticum (Breb.), not rare. 
