ORIGIN AND EVOLUTION OF LIFE
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��From the Burgess fauna it appears that the invertebrateB bad en- tered all the life zones of the continental and oceanic waters except possibly the abyssal. All the principal phyla — the segmented Aunu- lata, the joined Arthropoda (including trilobites, merostomes, cms-
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���Pio. 10. Lira ZONBB or Ciubbun ihd Bbl,itbd diaxiNa iHTBBiBBBma. Chart BhowlDg the contrast between the Uld-Cambrlan (lelt) and recent (right) pb^ln Br Rot W. Miner.
��taceans, arachnids, and insects), medusee and other coelenterates, echi- nodenns, brachiopodsj molluscs (including pelycypods, gastropods, am- monites and other cephalopods), and sponges — were all clearly estab- lished in pre-Camibrian times. Which one of these great invertebrate
���Life Zonbb or Invebtbdbateh, Cohpibsd 1 RiFTiLiB. BiBDa IND Mahualh. Cbart ebowlDg the eitenaloD bratea and iDTertebratea tbrongbouC the Tarlous babEtat lODea.
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