: 1907] Terry,— Partial List of Connecticut Diatoms 129 
looking in the water like enormous sponges, but collapsing when 
gathered into a rope of harsh feeling filament, about two feet long, 
which held great numbers of other diatoms, among them another 
new Pleurosigma, quite small. I sent all three to Tempére, he passed 
them on to Peragallo, who published illustrated descriptions of them 
in his monograph ! which is now the accepted standard for Pleuro- 
sigma. Peragallo named the largest one P. Terryanum, the second 
P. Americanum, and the third P. paradoxum. He describes the first 
as having the outline of P. strigilis W. Sm., but the striation of P. 
balticum; the second having the outline of P. elongatum W. Sm., 
but striation of P. decorum W. Sm.; and the third was named P. 
paradoxum because the least approximate of its series of striae was the 
most difficult to resolve. I afterwards found P. Terryanwm more 
abundant and larger in a broad ditch at Quinnipiac, and in a pond 
at Leete's Island. Its natural habitat is in brackish water fed by 
fresh water springs and too nearly fresh to support P. balticum. With 
this is often found P. elongatum, and also the robust type of Surirella 
striatula and a peculiar variety of Navicula permagna (Bail.) Ehrenb. 
The normal type of N. permagna is abundant in Oyster River, Wood- 
mont. The species of Pleurosigma are found with it at Leete's Island, 
and also a remarkable colony of Navicula maculata Bail., which occurs 
here in great abundance, and in three distinct types; the largest is 
extremely rare elsewhere, the second found occasionally along the 
Connecticut shore, and the third and smallest is the most common. 
I have it from the New Jersey shore and from Cuxhaven, North Sea. 
A much smaller variety but with coarser puncta is found in Alabama. 
The typical P. Terryanum is the largest Pleurosigma that I find in 
Connecticut; P. Americanum is abundant in tidal creeks; in the 
marsh on the West Haven side of West River, on the muddy slop- 
ing bank of a ditch, I have seen at low tide a brown film about two 
feet wide and a hundred feet long, which consisted almost entirely 
of living frustules of P. Americanum. P. paradoxum is most abun- 
dant in Morris Creek, occasional elsewhere. Morris Creek is also the 
habitat of Actinocyclus Barkleyi (Ehrenb.) Grun., which is living here 
in abundance. I have it also in considerable numbers from the Thames 
river above Norwich in material sent me by Mr. G. R. Lumsden of 
Greenville. 
1 Peragallo, Monographie du genre Pleurosigma, Le Diatomiste, Vol. I. 
