OPEPHORA PINNATA VAR. LANCEOLATA N. VAR.
Valve lanceolate; costæ slightly radiate, punctate; median area broad, lanceolate.
Differs from O. pinnata in outline, radiation of the costæ and median area.
Blue clay. Rare.
Pl. [10], Fig. 17.
FRAGILARIINÆ
Fragilaria.—Frustules in fasciæ. Valve with transverse striæ. Pseudoraphe indistinct.
Rhaphoneis.—Striæ radiate; pseudoraphe distinct.
Dimerogramma.—Pseudoraphe broad.
Trachysphenia.—Valve cuneiform.