ATJLOrOMA — PTEROCYCLUS. 97 



Orif/inal description (in German) : — " It is flat, almost disk- 

 shaped, with a very acnte, scarcely projecting spire, very deep 

 suture, wide umbilicus, and it is yellowish in colour, with brown 

 bands and markings. Diam. 8'"." (TroscJiel.) [16x12x7 mm.] 



Hah. Ceylon. 



13G. Aiilopoma sphajroideum, Dohm. 



Au/oponia s/>h(eroideiim, Dohru, Malak. Blatter, iv, 1857, p, 85; 

 Pfeiffer, Mon. Pneum. Suppl. 1, 1858, p. 39; II. Nevill, Enum. 

 Helic. Pneum. Cevlon, 1871, p. 5 (A. spheroideiun) ; Theobald, 

 Cat. Shells Brit, liidin. 1876, p. 37 ; Nevill, Hand List, i, 1878, 

 p. 279; Kobelt & M511endorfF, Nachr. Dents. Malak. Oe.s. xxix, 

 ] 897, p. 113; id., Cat. Pneum. 1899, p. 2o ; Kobelt, Das Tierreich, 

 Lief. 16, 1902, p. log. 



Original description: — " T. anguste umbilicatn. conoidea- 

 globiilos:i, tenuis, striatula, sub epidermide fulva albida, obsolete 

 rufo-maculata ; spira conoidea, apice nigricans, acutiuscula ; anfr. 

 vix ultra 4 rapide accrescentes, 2 ultimi turgidi, ultimus antice 

 breviter soliitus ; apertura obliqua, circularis, superne levissime 

 subaugulata ; perist. simplex, rectum. — Operc pallidum, extus 

 medio excavatiim, anfr. 5 convexis, oblique striatis. — Diam. 

 maj. 13J. min. Hi, alt. 9 mill. Ap. diam. 6| mill." 



Ifab. Ceylon (Nietner). 



Genus PTEROCYCLUS, Benson. 



Pterocyelo.% Benson, J. A.S. B. i, 1832, p. 11 ; id., Zool. Journ. v, 1834 



p. 462; id., J.A. S.B. V. 1836, p. 3o6 ; Troschel, Zeits. Malak. 



iv, 1847, p. 44; Benson, A. M. N. H. ser. 2, i, 1848, p. 345; 



Pfeiffer, Conch.-Cab., Cyclostomaceeu, 1849, p. 193 ; Gray, 



Xoniencl. Moll. Brit. INIus. i, 1850, p. 11 ; Pfeiffer, Zeits. Malak. 



viii, 18.")1, p. 135 ; id., Mon. Pneum. 1852, p. 41 ; id.. Cat. 



Phaneropn. Brit. ]\[us. 1852, p. 25; Adams, Gen. Rec. Moll. 



ii, 1855, p. 277; Cbenn, Man. Conchyl. i, part 2, 1860, p. 486; 



Martens, IVuss. Exped. Ost-Asien, Zool. ii, 1867, p. 114. 

 Pterocycliis, Nevill, Hand List, i, 1878. p. 260; Fischer, Man. 



Conchvl. 1885, p. 745; Kobelt & Mollendorff, Nachr. Dents. 



Malak! Ges. xxix, 1897, p. 113; id., Cat. Pneum. 1899, p. 25; 



Kobelt, Das Tierreich, Lief. 16, 1902, p. 160; id., Conch.-Cab., 



Cyclophoridae, ii, 1909, p. 719. 

 Steganotoma, Troschel, Arch. Naturg-. iii, part 1, 1837, p. 163. 



Type, Pterocyclos rupestris, Benson. 



Banf/e. India, Farther India, Ceylon, Southern China, Malaysia. 



Shell discoid, somewhat convex above, concave below, and 

 widely umbilicated; whorls cylindrical, slightly adhering together, 

 and visible on both sides. Sutures channelled. Peristome reflected, 

 interrupted at the summit of the aperture by an oblique sinus. 

 Outer lip furnished, at the upper part, with an arched wing, which 

 overhangs the sinus. Wing broad, tumid, bending downwards and 

 mucronate in front, adhering to the penultimate whorl. Oper- 

 culum multispiral, convex outside, the edges of the whorls slightly 

 raised, concave inside. 



H 



