The mid-Ordovician saw the main cephalopods with septa potent more than enough to manage Along with the pressures linked to deeper h2o, and will inhabit depths higher than a hundred200 m.[139] The course of shell coiling would demonstrate for being crucial to the longer more term good results of the lineages; endogastric coiling would only allow huge size to get attained having a straight shell, Whilst exogastric coiling originally rather