44 
PTEROCYCLOS §.2.3. 
Cyclostoma planorbulum Voigt in Cuv. Thierr. III. p. 177. 
— — Sow. Thes. t. 25. f. 83. 
— — Chemn. ed. II. t. 29. f. 16. 17. 
— — - Petit in Journ. Conch. I. p v 43. 
Cyclotus planorbulus Swains. Malacol. p. 336. 
— — Gray Catal. Cycloph. p. 8. (ex parte.) 
Plerocyclos planorbulus Pfr. Consp. N. 47. 
Habitat in insula Java? Borneo? 
§• 3. 
75 4. Ft. Troschell Benson, f 
T. latissime umbilicata, orbiculato-depressa ; anfr. 4 lente 
accrescentes , ultimas 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. VUI. 1851. Ang. t. 5. f. 2. 
— — Pfr. Consp. N. 48. 
Habitat ad Trincomalee insulae Ceylon (Bland). 
Obs. „Affinis Myxostomati Trosch.“ 
76 5. PI. anguliferiis Sonleyet. 
T. late umbilicata, discoidea, solida, laevigata, nigricanti- 
castanea, albido irregulariter flammulata ; spira plana; anfr. 
vix 5 convexiusculi, ultimas non descendens ; apertura obliqua, 
subcircularis , 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. — 
Operc. extus conicum, lamella late 3 — 4-spirata circumvolutum, 
vertice glabro, intus laevigatum, corneum. — Diam. maj. 24, 
min. 18, alt. 6 */ a mill. Ap. diam. 8 mill. (Coll. Nr. 26.) 
Cyclostoma angulifera Soul, in Revue zool. 1841. p. 347.*) 
*) T. suborbiculari , 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 sulcato, carinis lamel- 
losis , vertice piano , subtus concavo , margaritaceo. — Diam. 22 mill. 
(Soul. 1. c.) 
