als ▁in ▁Maine ▁ ▁Transport ation ▁in ▁Maine ▁ ▁Air ports ▁in ▁Maine ▁ ▁Rail ▁transport ▁in ▁Maine ▁ ▁Education ▁in ▁Maine ▁▁ ▁Education ▁in ▁Maine ▁ ▁School s ▁in ▁Maine ▁ ▁School ▁districts ▁in ▁Maine ▁ ▁High ▁schools ▁in ▁Maine ▁ ▁Colleg es ▁and ▁univers ities ▁in ▁Maine ▁ ▁University ▁of ▁Maine ▁ ▁See ▁also ▁ ▁Top ic ▁over view : ▁Maine ▁ ▁Index ▁of ▁Maine - related ▁articles ▁ ▁References ▁ ▁External ▁links ▁▁ ▁Maine ▁Maine <0x0A> </s> ▁The ▁P ty ch it idae ▁is ▁a ▁family ▁of ▁cer at it id ▁am mon ites ▁( am mon ites ▁sens u ▁l ato ). ▁They ▁are ▁combined ▁with ▁the ▁E os agen it idae ▁and ▁St uri idae ▁in ▁the ▁super family ▁P ty ch it aceae . ▁ ▁P ty ch it id ▁gener a ▁have ▁com pressed , ▁invol ute ▁shell s ▁in ▁which ▁the ▁inner ▁wh or ls ▁are ▁covered ▁by ▁the ▁outer most , ▁that ▁may ▁be ▁rib bed ▁or ▁smooth , ▁and ▁am mon it ic ▁s ut ures ▁with ▁secondary ▁elements . ▁ ▁References ▁▁▁ ▁Ark ell , ▁et ▁al ., ▁ 1 9 5 7 . ▁Mes oz o ic ▁Am m ono idea , ▁in ▁the ▁Tre at ise ▁on ▁In verte br ate ▁Pale ont ology , ▁Part ▁L ▁. ▁R . ▁C . Mo ore ▁( ed ). ▁Ge ological ▁Society ▁of ▁America ▁and ▁Un iv ▁of ▁Kansas ▁press . ▁ ▁P ty ch it idae - P ale odb ▁▁