It is part of a phylum whose other classes include bivalves and gastropods.
Most male members of this taxonomical class have an arm-like structure used to transfer sperm to females called the hectocotylus. One member of this taxonomical class has a large axon that was used by Hodgkin and Huxley to study nerve conduction. Extinct members of this class include belemnoids and ammonites. It is part of a phylum whose other classes include bivalves and gastropods. Most members of this class can release "ink" when threatened by predators. For 10 points, name this class of mollusks whose members include the nautilus, squid, and octopus.
Most male members of this taxonomical class have an arm-like structure used to transfer sperm to females called the hectocotylus.
{cephalopod}s [or {Cephalopoda}]