There are four types of cephalopods:

1) Octopi--they have eight symmetric arms (tenticles) which are used for their protection and for obtaining food. They have an interesting mating ritual: The males and females do not mate with any other partners besides the chosen one. Shortly after the female has her children, she dies, but the male stays with her--he does not mate again. This example is one of the only monogamous relationship that exists among animals. The octopus also has the most advanced sensory systems of any other invertebrate.

2) Squids--have ten polymorphic arms--two special arms that an octopus doesn not have. They use Rajiform (after Raja=skate) swimming motions in which they undulate their lateral fins like a skate or ray does. They also have something called jet propulsion. This is caused by the squid taking water into its mantle cavaties and then expelling it at high speeds through a nozzle like siphon in the opposite direction that the squid wants to move. The siphon can be aimed in any direction for course corrections and maneuvering purposes. The squid uses its tenticles for food and for protection. The myth of the Giant Squid is in fact true. It is a very shy creature and is usually only seen if it dies and washes up on shore.

3) Cuttle Fish--have ten polymorphic arms (2 special arms that the octopus does not have). They also use their lateral fins to swim in the same manner of the squid. The remnants of its shell are internal--makes a well-developed internal skeleton. They like to inhabit areas around CORALS.

4) *The Chambered Nautilus--is the only cephalopod with a true shell. The shell is made of many chambers. The nautilus normally inhabits deeper waters so there is less known about its life than the other cephalopods.


*Pictures to be added at the end of summer 1999!*