750 
38. Pterocyclus niahensis G. Austen. 
Taf. 109. Fig. 9. 10. 
Testa discoidea, latissime perspectiviter umbilicata, sub epidermide crassa subtiliter 
striata, brunnea, strigis angustis fulguratis regulariter dispositis ornata; spira plana apice 
haud prominulo; sutura vix impressa; anfractus 5 subangulati, ultimus ad angulum lira ele- 
vata, supra liris minus distinctis 2, infra 3 sculptus. Apertura circularis, perobliqua; peri- 
stoma duplex, internum Simplex, continuum, externum valde expansum et reüexum, supra 
valde expansum et plicam suturalem fere tubuliformem formans, dein in alam margine 
sinuato depressum. — G. Austen angl. 
Diam. maj. 27,75, min. 23, alt. 5,5, alt. anfr. ult. 11,5 mm. 
Pterocyclus niahensis Godwin- Austen, in: Pr. zool. Soc. London 1889 p. 340 
t. 35 fig. 3. — Kobelt & Moellendorff, Catalog, in: Nachrbl. D. 
malak. Ges. 1897 vol. 29 p. 113. — Kobelt, Cyclophoridae, in: 
Tierreich, Heft XVI p. 167 (mit var. baramensis fig. 35). — 
Schepman, in: Notes Leyden Museum, vol. 17 p. 158. 
„Shell dextral, discoid, very widely perspectively umbilicated, sculpture a thick 
epidermis, crossed by stony lines of growth; colour umber- brown, witli narrow 
zigzag markings Crossing the whorls at regulär intervals; apex not raised above tlie 
succeeding whorls; suture shallow; whorls 5 subangulate at the periphery, with a 
raised rib upon it, two similar less defined ribs above and three on the under- 
side; aperture circular, very oblique; peristome double, inner continues simple, the 
outer much expanded and reflected, particularly on the upper margin, where it 
forms one strong sutural fold, which a very slight further depelopment would con- 
vert into a tube, it then falls over in front forming a frontal lappret, with sinuate 
edge. — Operculum dark brown, multispiral, with coarse raised edges in front, 
deeply concave below.“ — GA. 
Aufenthalt in den Niah-Bergen in Borneo, eine flachere Form mit eingesenk- 
tem Apex (var. depressus G. Austen *) in den Molu-Bergen in Nordborneo. Die 
von mir abgetrennte Form aus dem Baram-Gebiet mit weniger kantigem letztem 
Umgang und schärferer Skulptur (var. baramensis) vgl. oben p. 15. 
*)’ It differs in three particulars, viz. in the form ef the wing beiDq less developed into the tnbnlar 
form; in the apical whorls depressed below the succeeding whorls; in the coloration being of a darker tint 
with broader zigzag blotchings. 
