FIG. 4 in Small naviculoid species of Kobayasiella Lange-Bertalot, Adlafia Moser, Lange-Bertalot & Metzeltin, Nupela Vyverman & Compère and Sellaphora Mereschowsky from Tursujuq National Park, Hudson Bay region, Nunavik, Québec

FIG. 4. — SEM images of Kobayasiella parasubtilissima (Kobayasi & Nagumo) Lange-Bertalot: A, external view of the complete valve; B, internal view of the valve areolae recessed between virgae; C, section of girdle band showing one row of evident pore and a second row of scattered less evident pores with volae covers; D, external view of the axial and central areas showing the multiseriate poroid covers between the virgae; E, internal view of the central area showing T-shaped proximal fissures; F, central area with a weak central depression; G, external view of the valve apex, showing a partially curved proximal fissure opening into a small round surface depression; H, internal valve view of the apex. Helictoglossa expanded onto a highline apex. Areolae continuous around the apex. Scale bars: A, 10 µm; B-E, H, 1 µm; F, 600 nm; G, 3 µm.