General Anatomy
(Yotso-Yamashita, 2007)
M. maculosa: Generally one inch across. Approximately the size of a golf ball
Life Span: 2 years
Beak: modified radula that is used for eating clams and other prey
Poison Gland: Used to produce Tetrodoxin that is used for both defense and hunting purposes
Ink Sac: Used to produce ink that can be released and used as a veil to get away
Eye: Compound eye that is used to form an image
Arm: Eight arms that have dual sets of suckers
Chromatophores: used for camouflaging with the environment
Iridiophores: used to send a warning by flashing blue rings on the body surface
Mouth: located underneath the central part of the octopus in the middle of the arms
Males have a modified arm that is has a seminal channel to transfer a spermatophore to the female
Have a closed circulatory and digestive system
Locomotion: They can move by propulsion and also by using their legs to walk on the ocean floor
Life Span: 2 years
Beak: modified radula that is used for eating clams and other prey
Poison Gland: Used to produce Tetrodoxin that is used for both defense and hunting purposes
Ink Sac: Used to produce ink that can be released and used as a veil to get away
Eye: Compound eye that is used to form an image
Arm: Eight arms that have dual sets of suckers
Chromatophores: used for camouflaging with the environment
Iridiophores: used to send a warning by flashing blue rings on the body surface
Mouth: located underneath the central part of the octopus in the middle of the arms
Males have a modified arm that is has a seminal channel to transfer a spermatophore to the female
Have a closed circulatory and digestive system
Locomotion: They can move by propulsion and also by using their legs to walk on the ocean floor
Iridiophores
(Mathger, 2012)
Iridiophores are used to display the approximately 60 bright blue colored rings that show up as a warning sign to any oncoming threat. They are able to flash these rings in approximately .3 seconds. No chromatophores are located above the rings. When they are feeling threatened they darken the chromatophores that are located around the rings. This is to provide more contrast for the rings. The rings are able to show quickly due to the fact that they have direct nerve connection to fast twitch muscle fibers. In order to expose the rings, they relax the muscles inside of the ring and contract those surrounding. The rings are always lit up but they aren't always visible because of the tissue that is usually covering them. This technique is unusual for cephalopods. Generally they use hormone control for color changes (Mathger, 2012)
In the video located below you can see the color change that the octopus can do and the locomotion style it uses.
Eye
http://www.bio.miami.edu/
Due to the decreased UV radiation that is found underwater, it means that they are able to have their eyes oriented differently than the human eye. In the octopus eye, the photoreceptors are the first thing that the light hits (Wolken, 1958). This allows them to take advantage of the limited light source they have and to develop a more clear image. They also do not have a blind spot from where the optic nerve attaches to the eye. If terrestrial animals were to have eyes oriented this way they would damage the photoreceptors from the UV radiation.