= 
340 LIEUT.-COL. H. H. GODWIN-AUSTEN ON [June 18, 
19. PrerocycLos MINDAIENSIS, Bock. 
Pterocyclos mindaiensis, Bock, P. Z.S. 1881, p. 634. 
Near P. loweanus, Pfr., but larger. 
20. PreROCYCLOS NIAHENSIS, n. sp. (Plate XXXV. figs. 2, 3a.) 
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, par- 
ticularly 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. 
Sine : 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. cucullus 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- 
ing whorls ; in the coloration being of a darker tint with broader 
zigzag 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. PrerocycLos CUCULLUS, n. sp. (Plate XXXV. figs. 2, 2a.) 
Shell dextral, flatly discoid, very amply and perspectively umbili- 
cated; 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 in 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. 
Hab. Niah Hills. 
Pterocyclos eudedalus, Crosse, Journ. Conch. xvii. 1869, p. 187. 
Hab. Borneo. 
