MICROSPORA 167 
On rock or earth in rapids of grassy meadow streams. 
Thomaston, Conn., May (568). 
This species has a superficial resemblance to ى‎ fuitans, but 
differs from it in the strong tendency of the filaments to stability, 
and in the much clearer green and clean-cut character of the 
chromatophores, with their more distinct pyrenoid. The genic- 
ulations in this species have a much more permanent character 
than those of S. fuitans; there they appear to arise simply from 
the excessive tendency to dissociation of the cells, while here they 
arise from the irritation of cells as they are pressed upon the sub- 
stratum by the current. The rhizoidal structures are here very 
different from the basal cells in Ulothrix, their cell-walls are 
thickened only in a slight degree, and the chromatophore retains 
nearly its normal character; there is every evidence that here 
they are always developed secondarily as tendril-like organs, and 
not at the germination of the zoospore as in Ulothrix. Zoöspores 
were not formed freely in our specimens, though some cells from 
which they had emerged were found. 
There appears to be no sufficient raison d’être for Wolle's var. 
cataracta since the characters on which it is founded are mentioned 
in Kützing's descriptions of the species. 
III. MICROSPORA Thuret, Ann. Sci. Nat. Bot. III. 14: 221. 
1850. Lagerh. Ber. Deutsch. Bot. Gesell. 5: 413-417. 1887. 
Flora, 72: 207-209. 1889. Not Microspora Hassall, Ann. 
& Mag. Nat. Hist. 11: 363. May, 1843 (= Cladophora Kitz. 
Linnaea, 17: 91. 1843).* 
Filaments simple, generally unattached and with little differ- 
ence between base and apex. Chromatophore a granular band or 
sheet covering more or less completely the outer cell-wall and the 
dissepiments, sometimes perforate or reticular, without pyrenoids 
Hassall's genus Microspora had for its type Conferva glomerata L. and would 
supplant Kützing's C/adophora if it should be proved that Hassall's work was published 
earlier in the year 1843 than Kützing's. Probably, however, Kützing's work in the 
first Heft of Linnaea appeared earlier than May, the published date of Hassall's paper. 
Hassall (”45) himself abandoned his Microspora in favor of Kützi tzing's Cladophora. 
Since, 7ئ سر‎ Ug Hassall is never likely to be taken up again, it has been 
thought best to e a too strict application of the article of the Rochester Code in 
regard to Bee and to retain the only Aficrospora that has ever been in general 
use. 
