Trachyneis CLEVE (1894)
(trachys, rough, and neis (naus), named from the chief species)
Valve more or less linear or linear-lanceolate. It appears to be composed of three strata, one an interior, coarsely dotted, an exterior of fine puncta in longitudinal striæ, scarcely visible, and a median of transverse anastomosing costæ forming irregular alveoli.
Chromatophores, two or four bands on the zone (Mereschkowsky).
TRACHYNEIS ASPERA VAR. INTERMEDIA GRUN.
Valve linear-elliptic; axial area a stauros widened outward and unilateral. Striæ of the median layer of radiating rows of oblong alveoli.
Along the coast. Not common.
Pl. [17], Fig. 15.
The type form and its numerous varieties are quite ubiquitous. Very large specimens occur in the Antarctic regions, especially in material from Ross Island, S. Victoria Land (Shackleton Ant. Exp.).