44 PTEROCYCLOS 68.2.3. 
Cyclostoma planorbulum Voigt in Cuv. 'Thierr, HI. p. 177. 
— — Som. 'Thes. t. 25. f. 83. 
xs em Chemn. ed. II. t. 29. f. 16. 17. 
— — Petit in. Journ. Conch. I. p. 43. 
Cyclotus planorbulus Swains. Malacol. p. 336. 
— — Gray Catal. Cycloph. p. 8. (ex parte.) 
Pierocyclos planorbulus Pfr. Consp. N. 47. 
Habitat in insula Java? Borneo? 
$. 3. 
75 4. Pt. Troscheli Benson. 1 
T. latissime umbilicata, orbiculato-depressa; anfr. 4 lente 
accrescentes, ultimus antice subdilatatus; apertura circularis ; 
perist. incrassatum, reflexum, superne antice obsolete sinuatum, 
ala cucullata, antice angulata, deflexa, anfractui penultimo ad- 
haerente. —  Operc. convexum, corneum. — Diam. */,". 
(Bland.) — Diam. maj. 20, min. 18 mill. ex ic. (B.) 
Pterocyclos Troscheli Bens. in Ann. and Mag. VIII. 1851. Aug. t. 5. f. 2. 
— — Pfr. Consp. N. 48. 
Habitat ad Trincomalee insulae Ceylon (Bland). 
Obs. ,Affinis Myxostomati "Trosch.* 
16 5$. P't. anguliferus Souleyet. 
T. late umbilicata, discoidea, solida, laevigata, nigricanti- 
castanea, albido irregulariter flammulata; spira plana; anfr. 
vix 5 convexiusculi, ultimus non descendens ; apertura obliqua, 
subcireularis, intus fulvescenti-margaritacea; perist. duplex: 
internum breviter expansum, superne vix incisum, externum 
album, late expansum, superne ad anfractum penultimum in 
rostrum. obtusum, subtus profunde excavatum, dilatatum. — 
Opere. extus conicum, lamella late 3— 4-spirata circumvolutum, 
verüce glabro, intus laevigatum , corneum. — Diam. maj. 24, 
min. 18, alt. 6'/, mill. Ap. diam. 8 mill. (Coll. Nr. 26.) 
Cyclostoma angulifera Soul. in Revue zool, 1841, p. 347. *) 
*) TT. suborbieulari, superne planulata, subtus late umbilicata; anfr. 5 
convexo-depressis, interdum obsolete costulatis, rufo-nigricantibus, transver- 
sim levissime striatis; apertura rotunda, supra angulosa, angulo supra con- 
vexo, subtus fornicato; perist. crasso, reflexo, albo, submargaritaceo, intus 
marginato; operc.laevi, convexo, spiratim carinato et suleato, carinis lamel- 
losis, vertice plano, subtus concavo, margaritaceo. — Diam. 22 mill. 
(Soul. l. c.) 
