FIGURES 140–145 in The biogeographic distribution of Cavinula (Bacillariophyceae) in North America with the descriptions of two new species

FIGURES 140–145. SEM micrographs of Cavinula cocconeiformis f. elliptica (Hustedt) Lange-Bertalot. Figs 140, 142, 144, 145. External valve view. Figs. 141, 143. Internal valve view. Figs 140–145. Weinfelder Maar, Eifel, Rheinland-Pfalz, Germany (type material). Scale bars: 2 µm in Figs 143–145; 5 µm in Figs 140–142.