Hypselostoma perigyra van Benthem Jutting, 1950
“The new species has some superficial likeness to Hypselostoma terae and H. megaphonum. In both the latter, however, the whorls are more evenly rounded and the umbilicus is narrower. Besides, H. perigyra has a more developed peripheral keel. From H. megaphonum it differs in the smaller size and in the absence of the inflation on the base of the last whorl.” (Benthem-Jutting, 1949)
Benthem-Jutting (1949) original descriptions on Hypselostoma perigyra – “Shell consisting of a somewhat conical spire and a free trumpet-shaped last whorl. Dark reddish-brown, somewhat more yellowish-brown towards the aperture. First 1 ½ whorls smooth, polished, the others irregularly striated or weakly ribbed with oblique growth lines. There is no spiral striation. Not transparent. Whorls about 5, of which 4 ½ are regularly coiled and adnate, and about ½ whorl free and projecting. Whorls of the spire rounded, the greatest width below the periphery, so that the spiral whorls make the impression of having “lowered shoulders”. Suture deep. Last whorl with angulate periphery. The angulation becomes more and more a thread-like keel on the exterior lateral side of the free part. This keel continues till the aperture. Umbilicus open, though not wide. Aperture almost vertical, widened, trumpet-shaped. Peristome continuous, somewhat thickened and expanded. The mouth contains 4 rather strong teeth, placed cross-wise: one parieto-angular, one upper and one lower palatal, and one columellar. here is some variation in the length of the free part of the last whorl, some shells having a short, others a long trumpet. In addition to the four teeth of the mouth armature described above I found a fifth tooth, a short infraparietal lamella, in two shells from Bukit Takun.”
Hypselostoma perigyra – “Dimensions: Height – 2.6-3.2 mm; Breadth (with peristome) – 2.7-3.2 mm; Breadth (at origin of free part) – 1.8-2.1 mm; Height of aperture – 1.3-1.4 mm. (Benthem-Jutting, 1949)
Type locality – “Bukit Takun, Kanching, Selangor” leg. Benthem-Jutting/Mar. 1939 (Benthem-Jutting, 1949)