0 th - century ▁American ▁women ▁artists ▁Category : 2 1 st - century ▁American ▁women ▁artists ▁Category : W omen ▁m ural ists <0x0A> </s> ▁Ph ac el ool ith us ▁is ▁an ▁o ogen us ▁of ▁din osa ur ▁egg ▁found ▁in ▁the ▁D ong ting ▁bas in ▁of ▁the ▁Hun an ▁Province ▁of ▁China . ▁The ▁eggs ▁have ▁a ▁subs pher ical ▁shape , ▁meas uring ▁up ▁to ▁ 1 6 8 ▁mm ▁on ▁the ▁long ▁axis , ▁and ▁having ▁a ▁very ▁thin ▁shell . ▁ ▁Distribution ▁Ph ac el ool ith us ▁is ▁found ▁at ▁the ▁D ong ting ▁Bas in ▁in ▁Hun an . ▁They ▁are ▁dated , ▁on ▁the ▁basis ▁of ▁other ▁foss il ▁eggs , ▁ost rac ods ▁( seed ▁sh rim p ), ▁and ▁char oph y tes ▁( al ga e ) ▁found ▁at ▁the ▁same ▁site , ▁to ▁the ▁late ▁C ret ace ous . ▁ ▁Description ▁Ph ac el ool ith us ▁is ▁nearly ▁spher ical , ▁meas uring ▁ 1 6 7 – 1 6 8 ▁mm ▁long ▁and ▁ 1 4 0 – 1 5 0 ▁mm ▁across . ▁The ▁egg shell ▁is ▁very ▁thin , ▁meas uring ▁from ▁ 0 . 5 ▁to ▁ 0 . 7 ▁mm ▁thick . ▁Like ▁most ▁other ▁non - av ian ▁din osa ur ▁eggs , ▁Ph ac el ool ith us ''' s ▁shell ▁is ▁strat ified ▁into ▁two ▁layers : ▁the ▁pr ism atic ▁layer ▁on ▁the ▁outside , ▁and ▁the