/^ 



J . r»{ 



314 LIEUT-COL. H. H. GODWIN-AUSTEN ON [J line 18, 



margin at right angles to the hodv-whorl, and at last forming a flat 

 brrad wing, with a shallow fold near the suture. 



Size: maj. diam. 28v5, niin. 21'25: alt. axis 6'5 millim. 



Operculum shelly in front, multispiral, having the appearance of 

 a strand of rope coiled on itself, thin, flat, and horny on the inner 

 side. 



Hah. Molu Hills (/?. Hungerford) . 



31. Cyclotus TRUsANENSis, n. sp. (Plate XXXVI. figs. 5, 5ff.) 



Shell discoid, very widely unihilicated ; all the whorls showing ; 

 sculpture a thick epidermis, with lines of growth ; colour dark umber- 

 brown, with a few small splashings of cchre ; spire flatly depressed ; 

 apex fcarcely rising above the last whorl ; suture impressed ; whorls 

 5, rounded, the last slightly descending ; aperture circular, oblique ; 

 peristome double, inner simple, continuous, the outer slightly reflected, 

 gradually expanding towards the margin, forming at the suture a 

 small wing, which is attached to the penultimate M'horl. 



Size (of shell drawn): maj. diam. 18'5, min. 150; alt. axis 4'5 ; 

 diam. aperture 7'80 millim. 



Size(largest in collection): maj. diam. 22*5, min. 17'5; alt. axis 5'0; 

 diam. aperture 9'0 millim. 



Operculum shelly in front, flatly concave, with a small central 

 circular depression, horny at back, surface flat. 



Hah. Trusan Island (A. Everett). 



This shell without its operculum might on a casual examination 

 be referred to Pterocyclos tenuilahiatus, Metcalfe ; but it may be 

 distinguished from this latter by its closer umbilication and by the 

 last whorl not descending so rajndly. It is remarkable to find two 

 shells so very similar, and yet showing so wide a difference in the 

 form of the operculum. 



PterocycJos tennilnhiatus is quite plain in coloration, while Cyclotus 

 trusanensis shows bands of pale zigzag markings. 



2nd Group. Cycloti marmorati. 



Shell more or less turbinate, narrowly umbiHcate, smooth, with 

 marbled or fine zigzag markings. 



Cyclotus amboinensis, Pfr. 



Cyclophorus amboinensis, Pfr. P. Z. S. 1852, p. 144. 



Cyclotus amboinensis, von Martens, Preuss. Exped. Ost-Asien, 

 p. 121, pi. ii. figs. 4, 5. 



Hab. Borneo. In Cuming collection, Brit. Mus. 



This locality is doubtful ; von Martens gives it from the Moluccas 

 only, Amboina, Buru, &c. 



3rd Group. Cycloti suturales. 



Turbinate shells, openly umbilicate, plain in coloration, the last 

 whorl slightly separated from the antepenultimate. Peristome 

 simple, not reflected at all. 



