(terpsinoos, gladdening?)
Frustules quadrangular, adnate in filaments, usually free. Valve elliptical or triangular, with undulating sides divided by septa into three or more sections.
TERPSINOË AMERICANA (BAIL.) RALFS
Valve lobed at each end or angle. Central space rounded, hyaline. Surface with fine puncta in radiating lines.
Blue clay. Not common.
Pl. [6], Fig. 10.
TERPSINOË NOVÆ-CÆSAREÆ BOYER
Valve triangular, with concave sides and broad angles equally three-lobed, separated from the central part by septa. Central space small or absent. Puncta delicate, radiating or scattered. L. of side 62 µ.
Pleistocene clay at Buckshutem, N. J. Fossil at Wildwood, N. J.
T. americana, forma trigona Pant.? (Le Diatomiste, Vol. 2, p. 207.)