44 
OPISTHOPORUS. 
retro rsum euryato , rare fere verticali , rarissimeque antice 
versus directo, in speciminibus adultis circa l l ] 2 ad 2 mm. a 
margine aperturali distante, instructo; apertura circulari, am- 
pla, obliqua; peristomate in junioribus simplici, in adultis bre- 
viter bilabiato, margine labii interni paululum incrassato, saepe 
rubescente tincto, haud distincter discreto, externo expansius- 
culo, ambobus supra paulum productis atque prope suturam 
modice insinuatis. — Operculum discoideum , interne vix, 
externe distincte, concavum et album, multispiratum , medio 
corneo - testaceum , laminis duabus separatis ad peripheriam 
acutissimis. Diam. maj. 11,5, min. 9,5; altit. testae 6,6, diam. 
apert. int. 4, externe cum perist. 4,7 mm. 44 (St.) 
Opisthoporus Penangensis Stol. in Journ. As. Soc. XLI. Pt. 2. 1872. p. 
265. t. 10. f. 7. 
Habitat in insula Penang (Prince of Wales Island). 
Obs. „Proxime affinis 0. Sumatrano Mart.“ 
i6. 0. solutus Stoliczka. t 
„0. testa planorbulari, apice paulo exserta, late umbili- 
cata, corneo solidula; anfractibus 4 1 / 2 , fere teretibus, supra et 
infra paululum depressiusculis , sutura profunda ac simplici 
junctis , in spec, junioribus ad peripheriam sub - angulatis ; 
ultimo ad terminationem dissoluto, paulo expansiusculo modi- 
ceque deflexo, tubulo suturali antice directo, circiter 2 mm. a 
margine aperturali distante, instructo; anfractibus superioribus 
epidermide fusco-olivacea, transversim rugata, in ultimo fere 
simpliciter confertimque striolata, indutis, omnibus sub epider- 
midem albidis , sparse scrobiculatis , transverse minutissime 
striatis; apice albido; umbilico magno, anfractuum omnium 
maximam partem exhibente; apertura lata, circulari; peristo- 
mate duplici, interno tenui, paulum projiciente, externo undique 
modice dilatato, in facie antica concaviusculo et concentrice 
striato, in regione supra - suturali sensim producto, ambobus 
ad suturam anguste emarginatis. — Operculum normale, in 
utroque latere vix concavum, multispiratum, medio corneo- 
solidum. — Diam. maj. 15,5; alt. testae 7,3; diam. apert. int. 
4,3, ext. cum perist. 5,5 mm. 44 (St.) 
Opisthoporus solutus Stol. in Journ. As. Soc. XLI. Pt. 2. 1872. p. 266. t. 
10. f. 8—10. 
Habitat in insula Penang. 
