2. Serina cathaica Gredler, 1898

Figs. 1, 2 B–C; Tables 1, 3

Serina cathaica Gredler, 1898a: 11, T. F. 7.

Serina cathaica— Gredler, 1898b: 106. Yen, 1939: 87, pl. 8, fig. 20. Yen, 1942: 255. Chen, Zhou, Luo & Zhang, 2003: 442. Buliminus (Serina) cathaicus— Möllendorff, 1901: 360, pl.16, figs. 11–14. Kobelt, 1902: 862, pl. 123, figs. 11–14.

Type locality. Between Yulinkuan and Wenxian (Gansu) .

Material examined. ZI RAS (not numbered): 1 juv. NHM-1902.5.13.19 Reg.: 1 fms (measurements: wh 9.000, h 10.6 mm, w 2.8 mm, aph 3.0 mm, aw 2.4 mm); Gansu. SMF-42046: 4 fms.

Distribution. S Gansu.

Diagnosis. Shell with the most swollen part occurred at penultimate whorl. Whorls with a narrow, defined zone below the suture. Last whorl ascending immediately near aperture; straight at periphery; completely attached to body whorl. Aperture not duplicate.

Shell. Turrited, or ovate-turriform; dextral; with apex not abruptly pointed; with the most swollen part occurred at penultimate whorl; height 9.7–10.4–11.4, diameter major 2.8–3.0–3.3, ratio of height /diameter major 3.30–3.45–3.68. Growth lines fine and clear. Whorls 8 1/8–8 3/8–8 5/8, convex; with a narrow, defined zone below the suture. Embryonic shell 1 1/4–1 1/2+–2 whorls. Postnuclear whorls smooth. Last whorl ascending immediately near aperture; straight at periphery; with a rugate region with abapertural crowded and/or thickened growthline-like folds. Aperture in a plane and straight; ovate; almost vertical; completely attached to body whorl; height 2.7–2.9–3.4, width 2.0–2.4–2.8, ratio of shell height /apertural height 3.37–3.59–3.83. Aperture not duplicate. Peristome and parietal callus almost completely fusing except for a channel at upper insertion of peristome.

Reflexed part of peristome straight and not curved backward. Abapertural peripheral depression on body whorl spirally extending for ca. 1 whorl. Columellar margin reflexed. Columella arched. Umbilicus narrowly open. Shell uniformly chestnut, with aperture identically or brightly coloured. Measured specimens: SMF-42046, 4 shells.