Some specimens also have an arcuate black band over the forehead from one outer corner of the eye to the other.
Multifoil, mul′ti-foil, adj. having more than five foils or arcuate divisions.
The frustules are curved or arcuate (arcus, a bow) in the side view, oblong and narrowed at the ends in the front view.
Valve narrow, with arcuate dorsal and straight ventral margin, acute ...