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n.1.(Paleon.) An extinct genus of Paleozoic Cephalopoda, having a long, straight, conical shell. The interior is divided into numerous chambers by transverse septa.
References in periodicals archive ?
Looking more closely, though, you notice, emerging from the bottles' depths, the telltale signs of orthoceras -- those squid-like things that paleontologists claim used to use ice cream cones to dart around through Ordovician seas before becoming the stuff of limestone.
Genus: CODONELLOPSIS JAlrgensen 1924 Codonellopsis longa Kofoid and Campbell 1929 Codonellopsis morchella (Cleve) JAlrgensen 1924 Codonellopsis orthoceras (Haeckel) JAlrgensen 1924 Codonellopsis schabi (Brandt) Kofoid and Campbell 1929
Orthoceras strictum * * * Oxalis perennans * * * Pelargonium australe * * Phragmites australis * * * * Portulaca oleracea * * * Prasophyllum spp.
The graptolite fauna of the Lower Orthoceras limestone Halluden, Oland, and its bearing on the evolution of the lower Ordovician graptolites.