The mid-Ordovician saw the main cephalopods with septa potent plenty of to manage Together with the pressures connected with deeper h2o, and could inhabit depths greater than a hundred200 m.[139] The route of shell coiling would here show to be very important to the long run achievement of your lineages; endogastric coiling would only permit large dimensions for being attained with a straight shell, Whilst exogastric coiling at first alternatively