1907] Terry,— Partial List of Connecticut Diatoms 127 
In five different ponds in Bristol I have found an abundance of a 
new Surirella, and in one of these ponds it is the predominating form. 
It is about the size of S. gracilis A. Schm., but not so alate, and with 
rounded ends, costa distinct, reaching the median line, which is 
strongly marked; most specimens have a slight spiral twist. It occurs 
in two types, one greatly elongated. The living frustules are some- 
times covered with coarse granulations that do not come off in the 
acid treatment, but are removed by the soda. Prof. H. L. Smith 
wrote me “This Surirella is certainly new and much more deserving 
of a specific name than many others." Dr. Ward named it Surirella 
Terryi. I have found this species abundant in one small pond in 
New Britain and in one at Leete’s Island, but in all other localities 
known to me it is extremely rare. In Birge’s Pond in Bristol are 
countless numbers of a very peculiar abnormal form of Surirella. It 
is a double frustule in which the two inner valves are grown together 
with a perforation through the center where the protoplasm of the 
two cells joins. This opening is sometimes a mere raphe or cleft, 
more often it is a long narrow slit with smooth edges, but generally 
it is a large irregular orifice with corrugated sides. This peculiarity 
is most abundant in Surirella elegans Ehrenb., but frequent in S. cardi- 
nalis Kitton, and occasional, in S. splendida (Ehrenb.) Kütz. I found 
it first in S. striatula Turpin in an artificial culture of material from 
West River, New Haven. Mr. Richards brought me mud from a 
pond in Wallingford, in which I found it abundant in S. saxonica 
Auersw.; I have seen it in S. tenera Greg. and S. fastuosa Ehrenb., 
and have found it in Plymouth and in Derby. An illustrated de- 
scription was published in Tempére’s Micrographe Préparateur.! 
Nearly every marsh with a level surface covers a deposit of diatoms, 
and the salt marshes of the Connecticut shore are no exceptions. All 
of these that I have examined lie above a marine deposit, which 
generally appears like clay, but always contains diatoms and is some- 
times quite rich. The ancient channel of Leete's Island from Great 
Harbor on the south around to Shell Beach on the north, is one im- 
mense mass of marine deposit, in some places fifty feet thick. When 
the railroad crossing it was changed from a trestle to an embankment, 
the pressure of the great bank of earth forced out the marine mud 
1 W. A. Terry, Sur un étrange mode de développement chez le genre Surirella, Le 
Micrographe Préparateur, Vol. XIII, p. 57, 1905. 
