Sinoennea ridleyi (Peile, 1926)
“Compared with I. blanfordiana (Godwin-Austen), the genotype, the present species is larger and comparatively more obese; fewer of the early whorls are continuously costate. The angular lamella is wider and the parietal callus extends over a greater portion of the whorl. The palatal fold is bluntly conical without the tendency to become bifid observed in most examples of blanfordiana.” (Piele, 1926)
“Peile (1929, p. 154) figured an immature shell. It has four teeth which are, however, differently arranged from those in the adult shell.” (Benthem-Jutting, 1961)
Peile (1926) original descriptions on Indoennea ridleyi – “The shell is minutely perforate, sub-cylindrical, with eight whorls; the first two smooth, shining, the third and half the fourth regularly costate and smooth, but with a group of six fine growth-lines on the fifth and a similar group on the sixth whorl besides occasional single lines. There is also a group growth-lines on the last whorl behind the labrum. The base is wrinkled around the umbilicus. The early whorls are rather convex, the later ones flatter, but with well-marked suture. The peristome is milky white, well expanded and slightly reflected. The angular lamella is prominent and sinuous from front to back; it is joined externally on the one hand to the parietal callus, which lines a small sinus and connects with the labrum. The columellar lamina and the single palatal fold are in the corresponds to a pit in the exterior surface. The largest shell has been selected as the type. In two specimens the last two whorls are of slightly less diameter than the preceding one. In one of them the whole of the fourth whorl is costate.”
Benthem-Jutting (1961) descriptions on Sinoennea ridleyi – “Shell large, cylindrical, with blunt top. White, glassy transparent, shining. First 2 ½ whorls smooth, the three following ones transversely ribbed with equally spaced transverse ribs. After this the whorls are almost smooth, with an occasional irregular transverve rib (or couple of ribs), till on the last half whorl the ribs become again regular. Whorls 8 ½-10 (in the holotype in the British Museum nearly 9). Top whorls well rounded, later ones more flattened at the periphery. Suture distinct, but not deep. Umbilicus narrow, almost hidden by the last part of the last whorl. Aperture almost vertical, the lower part receding. Rounded-quadrangular, with two strong lamellae and one tooth. Peristome adnate, the parietal part attached to the penultimate whorl, covering almost the entire height of it. Free margins thickened and reflected. At the parieto-angular angle it possesses a distinct flexure, protruding as a high, sinuous ridge into the aperture. Columellar lamella deeply seated, not more than a blunt conical knob on a broad base. There is one palatal tooth, corresponding to a small pit on the exterior of the shell behind the peristome. Between this pit and the peristome the distal part of the last whorl is inflated.”
Indoennea ridleyi – “Length 8.3 mm; diam. 3.3 mm. Length of smallest shell 7 mm.” (Peile, 1926); Sinoennea ridleyi – “Dimensions: Height 7.0-9.1 mm; Width 3.0-3.2 mm; Height of aperture 2.3-3.3 mm.” (Benthem-Jutting, 1961)
Type locality – “seven miles from Kuala Lumpur, Selangor, probably on the limestone rocks near the Batu Caves” leg. H. N. Ridley/1897 (Peile, 1926)
Other locality – “Gua Tembus, Batu Caves, Selangor” (Benthem-Jutting, 1961)