38 PKOCEEDINGS OF SOCIETIES. 



Euastrum elegans a (Breb.), frequent. 

 „ binale (Turp.), not uncommon. 

 ,, sublobatum (Breb.), rare. 

 Cosmarium cucumis ( Corda), not common. 

 „ pyramidatum (Breb.), „ 

 ,, biocu latum (Breb.), „ 

 „ granatum (Breb.), rare. 

 ,, Meneghinii (Breb.), not uncommon. 

 ,, crenatum (Ralfs), rare. 

 ,, tetraopthalmum (Kut%.), rare. 



,, 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 differing in 

 having the deep constriction not forming a linear notch on 

 each side in the front view ; but wider at the outside, caus- 

 ing the angles at the base of the segments to be more 

 rounded ; the segments broadest at the base, 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] 

 ,, margaritiferum u, & (Turp.), frequent. 

 „ Brebissonii (Menegh.), not unfrequent. 



,, cselatum ( ), rare. 



,, cylindricum (Ralfs), rare. 

 „ cucurbita (Breb.), „ 

 „ phaseolus (Breb.), ,, 

 Xanthidium armatum (Breb.), frequent. 



,, t aculeatum (Ehr.) not uncommon. 

 „ cristatum ec & /3 (Breb.), rare. 



,, fasciculatum u (Ehr.), „ 



„ octocorne u. (Ehr.), frequent. [My opinion is that Xanthi- 



dium octocorne (var. u), 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 X octocorne seems out of place in it. Its affinity to 

 some forms of Arthrodesmus incus cannot but be apparent. 

 I have met with both species mixed in abundance.] 

 Arthrodesmus convergens (Ehr.), not uncommon. 

 ,, incus u & /3 (Breb.), not uncommon. 



Staurastrum dejectum, *, /3, & y (Breb.), frequent, 

 cuspidatum (Breb.), not unfrequent. 

 Dickiei (Ralfs), rare, 

 muticum (Breb.), not rare, 

 orbiculare (Ehr.), not uncommon, 

 tumidum (Breb.), rare ["Seechon" mountain.] 



