(sing. septum). - The thin walls or partitions between the internal chambers ( Camerae) of the shell are called the septa. As an ammonoid or nautiloid cephalopod grew it moved its body forward in the shell secreting septa behind it, thereby adding new chambers to the shell. The septa divide the phragmocone into camerae, and attached to the inside wall of the shell.
Internal partitions within the shell or skeleton of various types of animals, for instance, within the shells of ammonites.
The walls dividing the shell into chambers. The singular is 'septum'. Siphon A muscular nozzle present in most coleoid cephalopods used to direct the jet of water while swimming. Similar to the hyponome of the nautilus.
a dividing wall or membrane.
The internal walls between chambers of cephalopod shells.
In hard corals, the skeleton walls within a corallite, the skeleton formed by one polyp.