or inae '. ▁Lang ▁el uc id ated ▁in ▁detail ▁the ▁fa unal ▁and ▁strat ig raph ical ▁succession ▁of ▁the ▁Li as ▁along ▁the ▁Dor set ▁coast , ▁with ▁special ▁relation ▁to ▁am mon ites . ▁He ▁was ▁a ▁pro ponent ▁of ▁the ▁theory ▁of ▁orth ogen esis , ▁bel ieving ▁that ▁several ▁line ages ▁of ▁c rib rim orph ▁che il ost ome ▁b ry oz o ans ▁evol ved ▁progress ively ▁th icker ▁and ▁more ▁elaborate ▁ske let al ▁structures ▁which ▁eventually ▁became ▁mal ada pt ive , ▁driving ▁the ▁line age ▁to ▁ext inction . ▁ ▁By ▁extending ▁the ▁study ▁of ▁existing ▁British ▁species ▁of ▁mos qu ito es ▁to ▁their ▁four ▁lar val ▁stages , ▁previously ▁ill - known , ▁he ▁tested ▁the ▁relationships ▁already ▁infer red ▁from ▁imag inal ▁characters . ▁ ▁Later ▁life ▁Lang ▁ment ored ▁many ▁students , ▁who ▁came ▁to ▁use ▁the ▁facilities ▁of ▁the ▁British ▁Museum ▁( N . H .). ▁He ▁retired ▁from ▁the ▁British ▁Museum ▁( N . H .) ▁in ▁ 1 9 3 8 ▁and ▁moved ▁to ▁Ch arm outh , ▁Dor set , ▁where ▁he ▁had ▁hol iday ed ▁from ▁an ▁early ▁age . ▁In ▁ 1 9 4 0 , ▁Lang , ▁Stanley ▁Smith ▁and ▁H . ▁D ight on ▁Thomas ▁published ▁the ▁" Index ▁to ▁p ala e oz o ic ▁cor al ▁gener a ". ▁In ▁his ▁ret irement ▁Lang ▁wrote ▁several ▁articles ▁about ▁Mary ▁An ning , ▁the ▁foss il ▁collect or . ▁He