750 



38. Pterocyclus niahensis G. Auslen. 



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 reflexum, 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, 8. — Kobelt & Moellendorfif, 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, with narrow 

 zigzag markings crossing the whorls at regulär intervals ; apex not raised above the 

 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 circülar, 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 shght 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." — GrA. 



Aufenthalt in den Niah-Bergen in Borneo, eine flachere Form mit eingesenk- 

 tem Apex (var. depressus Gr. Austen*) in den Molu-Bergen in Nordborneo. Die 

 von mir abgetrennte Form aus dem Baram-Grebiet mit weniger kantigem letztem 

 Umgang und schärferer Skulptur (var. baramensis) vgl. oben p. 15. 



•),It differs in three partieulars, viz. in the form ef the wing beinq less developed into the tabniar 

 form; in the apical whorla depressed below the saeceeding whorls; in the coloration being of a darker tint 

 with broader zigzag blotchings. 



