Alzoniella elliptica (Paladilhe, 1874)
Shell ovoid, somewhat bulbous. The whorls are separated from each other by a deep suture, with a marked and almost horizontal subsutural ramp. Columellar margin oblique, weakly arched, thin, and not much reflected, letting appear a very narrow umbilical slit. Above: a specimen from Arnéguy area, between Roncesvalles and Saint-Jean-Pied-de-Port. 1,65mm. Altitude ≈ 270m.