Striatella, xliii, 326.
— arcuata, xliii, 226.f
Surirella, xlviii, 322.f
Symbolophora, characters of genus, xlviii, 203.
Syncyclia, xliii, 326.
Synedra, xliii, 322.f
Systephania, genus, xlviii, 325.
Tessararthra moniliformis, xli, 290.
Tessella catena, xlii, 102.f
Triceratium, xlviii, 336.f