FIGURE 17. Original type specimens of type species of Alternifenestella and Spinofenestella. (1) tangential section of Fenestella donaica (Lebedev) var. minor Nikiforova, 1933b (Middle Carboniferous, Bashkirian, Donets Basin, Ukraine), Paleontological Institute Moscow PIN 15/60a/33, type species of Alternifenestella; (2) tangential section of Fenestella spinulosa Condra, 1902 (Burr Limestone?, Lower Permian, Nebraska, USA), University of Nebraska paleontology collection 133311, type species of Spinofenestella. Scale bar equals 500 µm in Figure 17.1 for both photographs.