136 Rhodora [AvausT 
Amphora obtusa Greg. Frequent. 
a ovalis (Bréb.) Kütz. Frequent. 
Gomphonema acuminatum Ehrenb. Common. 
a constrictum Ehrenb. Common. 
capitatum Ehrenb. Common. | 
geminatum (Lyng.) Ehrenb. Common. 
augur Ehrenb. (G. cristatum Ralfs.) Common. 
Rhoicosphaenia curvata (Kütz.) Grun. 
Cocconers scutellum Ehrenb. Frequent. 
= dirupta Greg. Frequent. 
Achnanthes longipes Ag. Common. 
T brevipes Ag. Common. 
subsessilis Kütz. Fort Hale. 
*eurvirostrum Brun. Very rare, Morris Cove. 
*manifera Brun. Very rare, Morris Cove. — 
Achnanthidium flexellum (Kiitz.) Bréb. Rare; abundant in Bristol, 
fossil. 
Bacillaria paradoxa (Gmel.) Grey. Occasional near New Haven. 
N utzschia granulata Grun. Occasional. 
tryblionella Hantzsch. Frequent. 
= 3 var. maxima Grun. Occasional. 
plana W. Sm., Occasional. 
marginulata Grun. Occasional. 
acuminata (W. Sm.) Grun. Occasional. 
circumsuta (Bail.) Grun. Frequent. 
"t scalaris (Ehrenb.) W. Sm. Abundant. 
angularis W. Sm. Frequent. 
sigmoidea (Nitzsch) W. Sm. Frequent, locally abundant. 
sigma (Kütz.) W. Sm. Common. 
jasciculata Grun. Common. 
E obtusa W. Sm. Occasional. 
linearis var. tenuis (W. Sm.) Grun. (N. tenuis W. Sm.) 
Rare, Leete's Island. 
" curvirostris var. Closterium (Ehrenb.) VH. (N. Closterium 
W.Sm.) Rare, West Haven. 
Lorenziana Grun. Rare. 
E Shafjeri Cleve. (N. curvula Terry, not W. Sm.) Very 
rare, Morris Cove. 
Hantzschia amphioxys (Ehrenb.) Grun. Abundant in Bristol. 
i *segmentalis Brun. Rare, Morris Cove. 
Surirella biseriata (Ehrenb.) Bréb. Common. 
linearis W. Sm. Frequent. . 
robusta Ehrenb. Frequent in Winsted. 
xs splendida (Ehrenb.) Kütz. Common. 
tenera Greg. Common. 
elegans Ehrenb. Common. 
d " — var. norvegica (Eulen.) Brun. Occasional, Bristol. 
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