156 ULOTHRICACEAE 
Bright green, growing in short tufts or long tangled skeins ; 
cells cylindrical with strongly thickened outer wall, 10-25 ۸ in 
diameter, 14-34 as long, the septations thin; chlorophyll-band 
filling the length of the cell, containing (in the vegetative condi- 
tion) one distinct pyrenoid ; when the cell contents are preparing 
for formation of zoöspores, many pyrenoids may be seen in a cell 
(pl. 20, f. 7-9). 
Exsic.: Phyc. Bor. Am. 77, Nahant, Mass, March, 189r. 
'(W. A. Setchell). Ale Exsic. Am. Bor. Mystic River, Malden, 
Mass. (F. S. Collins). Hauck & Richt, Phyk. Univ. 729. Mystic 
River, Mass., March, 1889 (F. S. Collins). 
On Fucus and on leaves and culms of Spartina, etc. (rarely on 
rocks), between tide limits. Common on the New England coast 
and in New Jersey, at least as far south as Atlantic City. 
MAINE : Seguin Island, Aug. 30, 1900 (M. A. Howe, 238). 
Connecticut: Bridgeport, May (571). 
New York: Pelham Bay, April (12), April 18, 1901 (M. A. 
Howe); College Point, February (250, 251); Rosebank, Staten 
Island, December (231, 240); Livingston, April (326). 
New Jersey: Undercliff, Bergen county, April (310, 533); 
Atlantic City, Dec. 25, 1888 (I. Martindale). 
This species is very generally found growing on Fucus; on 
only one occasion have we seen it on rocks and shells. In this 
respect it is opposed to Hormiscia penicilliformis (Urospora) which 
is always found on rocks and timber, and never, so far as is known 
to us, on Fucus or grasses. Professor Wille (or) states that at 
Dröbak U. facca is found only on stones and rocks. He has created 
a new species, U. pseudoflacca, which seems to be distinguished from 
this only by such slight physiological or reproductive character- 
istics that we fail to see how he can determine which is the original 
U. flacca. Physiological characters are sometimes of importance, 
but it is questionable whether consistency would not demand the 
abandonment of the name U. flacca quite as much as that of U. 
implexa. 
Like most fresh water forms, this species usually disappears 
during the summer, but it probably forms a more luxuriant growth 
in late autumn and winter, while the fresh water forms do not de- 
velop extensively except in spring. 
PSE ee 
