How do you tell a boy octopus from a girl octopus?

[Lindsay McGuire]

My son, John, age 9, is doing a research project on the octopus , and is having a difficult time coming up with a comprehensible description of how to tell a boy from a girl. Can anyone help him out?
With profound thanks from Maine,
John's mother

 

[NickA5582]

I think male octo's are supposed to have enlarged sucker pads on the end of their tentacles, I'm not too sure though....

 

[NickA5582]

I think male octo's are supposed to have enlarged sucker pads on the end of their tentacles, I'm not too sure though....

 

[Steve O'Shea]

Hi John's mum (?Lindsay is it). How much time have you got? If the project can wait two days then I can get back in to work and respond with a couple of photographs of boy/girl characters. Basically the tip of the third right arm (or, rarely third left) of the male octopus is modified into a scoop/shovel (calamus/ligula) - there are no suckers at the end (the female has all 8 arms attenuating to fine, sucker-bearing tips.

There is a section online already that might help ('A guide to frequently used characters, states and measures') that has illustrations of this scoop/shovel (hectocotylus). Please see Figure 4 at http://www.tonmo.com/science/public/measurements.php

I'll post additional pics of whole animals in 2 days
Kindest
Steve