“In general outline the shape of the shell is intermediate between the Group IV and V. It has a higher spire than O. (O.) coronatum v. B. Jutting or O. (O.) trapezium v. B. Jutting and, therefore, should be regarded as a member of Group IV. The ornamentation, on the other hand, the flatter top and the wier umbilicus (although not so wide as in O. (O.) coronatum or O. (O.) trapezium suggest a classification in Group V. From O. (O.) tenerum v. B. Jutting the new species differs in the smaller number of ribs in the distal part of the last whorl, distally of the constriction. In this part the number of ribs is 11-12 in O. (O.) tenerum, but only 7-8 in O. (O.) hemistreptum. The new species differs from O. (O.) coronatum in the higher cylindrical shell, the narrower umbilicus and the position of the aperture which is directed obliquely backwards and only slightly upwards.” (Benthem-Jutting, 1961)
Benthem-Jutting (1961) original descriptions on Opisthostoma (Opisthostoma) hemistreptum – “Shell short-cylindrical. White, in fresh shells probably a little shining an transparent. Last whorl a little narrower than the preceding one. First whorl smooth, following ones ornamented with fine, white, distantly placed vertical ribs, standing off wing-like away from the shell. Between the ribs there is a fine spiral striation. Whorls 4 ½, the first small and little projecting, the others comparatively large and convex, separated by a deep suture. In the holotype there are 18 ribs on the last whorl, counting from the aperture to the spot where the distal part of the last whorl touches the penultimate one. On the penultimate whorl the holotype has 22 ribs. In the paratype from Ulu Kenyam Kechil, Ulu Tembeling, Pahang, leg. J. A. Hislop, April 1952 these numbers are 17 resp. 21. Distal part of last whorl directed upward and obliquely backward, adnate. Umbilicus open, but not wide. Aperture round, obliquely facing backward. Peristome continuous, circular or rounded-triangular, duplex. Operculum unknown.”
Opisthostoma (Opisthostoma) hemistreptum – “Dimensions: Height 1.0-1.1 mm, Width 1.3-1.45 mm, Diam. apert. 0.5 mm.” (Benthem-Jutting, 1961)
Type locality – “Malaya: Ulu Kenyam Kechil, Ulu Tembeling, Pahang” leg. J. A. Hislop/Apr. 1952 (Benthem-Jutting, 1961)
Other localities – “Malaya: Batu Besar, Ulu Kenyam Kechil, Ulu Tembeling, Pahang” leg. J. R. Hendrickson/Aug. 1954 (Benthem-Jutting, 1961)