▁and ▁ 2 4   mm . ▁ ▁The ▁el ong ated ▁shell ▁is ▁narrow ▁and ▁tur ret ed . ▁It ▁is ▁formed ▁of ▁nine ▁or ▁ten ▁very ▁distinct ▁wh or ls , ▁slightly ▁convex , ▁orn ament ed ▁with ▁a ▁great ▁number ▁of ▁rib s ▁formed ▁like ▁fol ds , ▁sub n od ul ous , ▁approximate , ▁numerous , ▁and ▁slightly ▁raised ▁upon ▁the ▁lowest ▁wh or l . ▁These ▁rib s ▁are ▁apparent ▁only ▁at ▁the ▁upper ▁part , ▁whilst ▁the ▁base ▁is ▁provided ▁with ▁trans verse ▁st ria e , ▁easily ▁distinguished . ▁The ▁a pert ure ▁is ▁ov ate , ▁and ▁strongly ▁not ched . ▁The ▁thin ▁outer ▁lip ▁is ▁sharp ▁and ▁rounded ▁at ▁the ▁lower ▁extrem ity . ▁The ▁col um ella ▁is ▁a ▁little ▁bent . ▁The ▁general ▁color ▁is ▁of ▁a ▁yellow ish ▁white , ▁orn ament ed ▁with ▁fer ru gin ous , ▁minute ▁lines , ▁and ▁with ▁a ▁surrounding ▁band ▁of ▁a ▁bl u ish ▁brown , ▁below ▁each ▁s uture . ▁The ▁body ▁wh or l ▁presents , ▁towards ▁its ▁base , ▁another ▁larger ▁and ▁deeper ▁colored ▁band , ▁which ▁is ▁obvious ▁within ▁the ▁a pert ure . ▁ ▁Distribution ▁This ▁species ▁occurs ▁in ▁the ▁Car ib bean ▁Sea . ▁ ▁References ▁▁ ▁B ouch et ▁P . ▁& ▁G of as ▁S . ▁( 1 9 8 3 ). ▁" T ere bra " ▁cos ent ini ▁Philipp i , ▁ 1 8 3 6 ▁an ▁American ▁col umb ell id