26 
OPISTHOPORUS. 
Testa depressa, orbicularis, late umbilicata, sutura pone 
aperturam tubulo exserto, pervio munita. Peristoma duplex. 
Opisthoporus Benson in litt. (Conf. Zeitschr. f. Malak. 1851. p. 8.) 
— Albers in Zeitschr. f. Malak. 1852. p. 120. (ex parte.) 
— Benson in Ann. and Mag. 1855. 2d. ser. XV. p. 13. 
— //. et A. Adams Gen. rec. Moll. II. p. 276: genus Cy- 
clotinarum. 
Pterocycli sp. Mouss. 
Cycloti sp. Pfr., Gray, 
Cl. Benson (1. c. p. 15) nomen generis cum Coelopo- 
mate mutari proponit, si species observarentur eadem operculi 
structura praeditae, sed tubulo suturali carentes. 
Species hodie cognitae sunt sequentcs : 
1. biciliatus !Iotis§. (Coll. 34. — Bens, in Ann. 
and Mag. 2d. ser. XV. p. 14. — Ad. Gen. II. p.276. 
t. 85. f. 2. — Pterocyclos bicilialus Mouss., Pfr. 
Mon. Pneum. p. 50. n. 16. — Gray Phan. p. 32. — 
C/iemn. ed. nov. p. 234. t. 43. f. 1 — 3. — Cyclo- 
stoma Taylorianum Pfr., Chemn. ed. nov. p. 288. 
t. 38. f. 27 — 29. — Cyclost. Charbonnieri Bed. 
in Journ. Conch. 1851. II. p. 214. t. 5. f. 12. 13.— 
Cyclotus Taylorianus Pfr. Mon. Pneum. n. 44. — 
Gray Phan. p. 24.) Mon. p. 40. 
2. O. euryoniplMilus Pfr. 
T. late umbilicata, depressa, subdiscoidea, solidula, stria- 
tula, lutescens, strigis angulosis castaneis superne latis, subtus 
linearibus picta; spira plana, vertice nigro vix prominulo; 
anfr. 4 4 / a , prope suturam canaliculatam subangulati, ultimus 
antice vix descendens, 4 mill, pone aperturam spiraculo brevi 
retroflexo munitus; umbilicus dimidium diametri fere occupans; 
apertura diagonalis, subcircularis ; perist. duplex: internum 
breviter expansum, ad anfractum penultimum subincisum, ex- 
ternum superne alatim dilatatum, latere dextro patens, sinistro 
obsoletum. — Operc. normale. — Diam. maj. 15, min. 12, 
alt. 4 mill. Ap. diam. 4 mill. (Mus. Cuming.) 
Cyclostoma euryomphalum. ( Opisthoporus) Pfr. in Proc. Zool. Soc. 1856. 
p. 337. 
Habitat in insula Borneo. 
0 b s. Differt ab 0 biciliato praesertim umbilico multo latiore. 
* 
3. rostellatug Pfr, (Bens, in Ann. and Mag. 2d. 
ser. XV. p. 14. — Ad. Gen. p. 277. — Cyclost. 
rost citatum Pfr in Chemn. ed. nov. p. 289. t. 38. 
f. 30 — 34. — Cyclotus rostellatus Pfr. Pneum. 
n. 45. — Gray Phan. p. 24.) Mon. p. 40. 
