▁in ▁ 3 D , ▁constructed ▁by ▁a ▁l ens ▁( or ▁less ▁than ▁half ▁of ▁a ▁circular ▁arc ) ▁rot ated ▁about ▁an ▁axis ▁passing ▁through ▁the ▁end points ▁of ▁the ▁l ens ▁( or ▁arc ). ▁The ▁cross - section ▁of ▁a ▁le mon ▁is ▁a ▁l ens . ▁ ▁Object s ▁that ▁typically ▁have ▁geometric ▁le mon ▁shape ▁or ▁similar ▁ ▁Similar ▁shapes ▁ ▁The ▁le mon - shape ▁is ▁similar ▁to ▁the ▁fus iform ▁( sp ind le - like ) ▁shape , ▁but ▁the ▁latter ▁often ▁implies ▁a ▁foc al ▁bro aden ing ▁of ▁a ▁structure ▁that ▁continues ▁from ▁one ▁or ▁both ▁ends , ▁such ▁as ▁an ▁an eur ys m ▁on ▁a ▁blood ▁vessel . ▁ ▁See ▁also ▁List ▁of ▁shapes ▁ ▁References ▁ ▁Further ▁reading ▁ ▁- ▁For ▁additional ▁mathematics ▁ ▁Category : Ge ometric ▁shapes <0x0A> </s> ▁Pr ist im ant is ▁d ors op ict us ▁is ▁a ▁species ▁of ▁f rog ▁in ▁the ▁family ▁Cra ug ast or idae . ▁It ▁is ▁en demic ▁to ▁Colombia . ▁Its ▁natural ▁habit ats ▁are ▁tropical ▁mo ist ▁mont ane ▁for ests ▁and ▁high - alt itude ▁grass land . ▁It ▁is ▁threatened ▁by ▁habitat ▁loss . ▁ ▁Im ages ▁ ▁References ▁ ▁d ors op ict us ▁Category : End em ic ▁fa una ▁of ▁Colombia ▁Category : Am ph ib ians ▁of ▁Colombia ▁Category : Am ph ib ians ▁of ▁the ▁And es ▁Category : Am ph ib ians ▁described ▁in ▁ 1 9