▁are ▁convex . ▁The ▁s ut ures ▁are ▁distinct . ▁The ▁body ▁wh or l ▁is ▁not ▁car in ated ▁at ▁the ▁peri ph ery , ▁rather ▁fl atten ed ▁on ▁the ▁base , ▁and ▁usually ▁slightly ▁er oded ▁in ▁front ▁of ▁the ▁a pert ure . ▁The ▁large ▁a pert ure ▁is ▁ob lique . ▁The ▁outer ▁lip ▁has ▁a ▁black ▁margin ▁and ▁is ▁within ▁sil very . ▁The ▁n acre ▁is ▁smooth , ▁but ▁apparently ▁l ir ate . ▁ ▁The ▁thin , ▁white ▁col um ella ▁is ▁ar cu ate ▁and ▁simple . ▁The ▁um bil ico - col um ell ar ▁region ▁is ▁surrounded ▁by ▁a ▁beautiful ▁rose - color ed ▁tract . ▁ ▁Distribution ▁This ▁marine ▁species ▁occurs ▁in ▁the ▁Atlantic ▁Ocean ▁off ▁Ang ola , ▁ ▁Nam ib ia ▁and ▁the ▁Cape ▁Region , ▁South ▁Africa . ▁ ▁References ▁▁ ▁Cont ribution s ▁to ▁the ▁knowledge ▁of ▁South ▁African ▁marine ▁M oll us ca ; ▁Ann als ▁of ▁The ▁South ▁African ▁Museum ▁vol . ▁ 4 7 ; ▁ 1 9 6 3 ▁ ▁External ▁links ▁▁ ▁G . B . ▁S ower by ▁( 1 8 9 2 ), ▁Marine ▁shell s ▁of ▁South ▁Africa : ▁a ▁catalog ue ▁of ▁all ▁the ▁known ▁species ▁▁ ▁A J H ▁Good win ; ▁Arch ae ology ▁of ▁the ▁O akh urst ▁Sh elter , ▁George : ▁Part ▁VI . ▁Str at ified ▁De pos its ▁and ▁Cont ents ; ▁Trans actions ▁of ▁the ▁Royal ▁Society ▁of ▁South ▁Africa