| OCR Text |
Show 340 LIEUT.-COL. H. H. GODWIN-AUSTEN ON [June 18, 19. PTEROCYCLOS MINDAIENSIS, Bock. Pterocyclos mindaiensis, Bock, P. Z. S. 1881, p. 634. Near P. loweanus, Pfr., but larger. 20. PTEROCYCLOS NIAHENSIS, n. sp. (Plate XXXV. figs. 3, 3 a.) 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 regular 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 underside ; 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 development would convert into a tube, it then falls over in front forming a frontal lappet, with sinuate edge. Size: maj. diam. 27*75, min. 23*0; alt. axis 5*5; body-whorl 11*5 millim. Operculum dark brown, multispiral, with coarse raised edges in front, deeply concave below. Hab. Niah Hills (A. Everett). This species is very like P. cuculius at first sight, but its keeled and ribbed whorls and the very different form of the winged expansion of the peristome separate it. A shell very similar occurs in the Molu Hills. It differs in three particulars, viz. in the form of the wing, being less developed into the tubular form ; in the apical whorls being depressed below the succeed-in**- whorls ; in the coloration being of a darker tint with broader zigza°* blotchings. This I distinguish as var. depressus. This shell was first found by Mr. Boxall and given to Dr. Hungerford, who presented a specimen to the British Museum, which I have seen. 21. PTEROCYCLOS CUCULLUS, n. sp. (Plate XXXV. figs. 2, 2 a.) Shell dextral, flatly discoid, very amply and perspectively umbilicated ; sculpture a thick epidermis with fine lines of growth ; colour pale sienna, with broad flame-like zigzag markings crossing the whorls transversely ; apex perfectly flat; suture impressed ; whorls nearly 5, rounded, rather rapidly increasing; aperture oblique, circular ; peristome double, the inner continuous, simple, the outer sharply reflected and increasing iu breadth on the outer margin, and the upper, where it droops over into a cowl-like shape, having one single depression or fold. Size: maj. diam. 26*0, min. 22*0; alt. axis 5*5; diam. ap. 8*5 millim. Operculum very dark brown, multispiral, with raised edges. Liab. Niah Hills. Pterocyclos eudcedalus, Crosse, Journ. Conch, xvii. 1869, p. 187. Hab. Borneo. |
