Valve constricted in the middle; apices sub-acute, sometimes slightly rostrate or capitate; central space evident.
Neshaminy Creek (Palmer). Blue clay. Crum Creek.
Pl. [11], Figs. 12 and 13.
SYNEDRA PULCHELLA (RALFS) KUETZ.
Valve lanceolate, tapering to the sub-acute, rostrate or slightly capitate apices; dilated at the central hyaline space; pseudoraphe distinct. Very variable in size.
Crum Creek. Schuylkill River. Rather common.
Pl. [11], Figs. 14, 15, 16.
SYNEDRA PULCHELLA VAR. ABNORMIS MACCHIATI?
Valve as in type form, except that one end is curved like a beak, as in S. hamata Wm. Sm., which it resembles.
Not uncommon in the Schuylkill River.