• Welcome to TONMO, the premier cephalopod interest community. Founded in 2000, we have built a large community of experts, hobbyists and enthusiasts, some of whom come together when we host our biennial conference. To join in on the fun, sign up - it's free! You can also become a Supporter for just $50/year to remove all ads and gain access to our Supporters forum. Follow us on Twitter and Facebook for more cephy goodness.

Anatomy question

Joined
Jun 21, 2020
Messages
70
In several of the popular cephalopod books I’ve been reafing, I have seen mention of a “skull” or “brain case”.
Am I correct in picturing this as a rather thin, cartilaginous structure giving some small protection to the brain. Obviously, it couldn’t be a BONY case, eh?
 
Joined
Jun 21, 2020
Messages
70
In several of the popular cephalopod books I’ve been reafing, I have seen mention of a “skull” or “brain case”.
Am I correct in picturing this as a rather thin, cartilaginous structure giving some small protection to the brain. Obviously, it couldn’t be a BONY case, eh?
Exceptionally flexible, compressible and pliable, too, I’d imagine.
 

DWhatley

Kraken
Staff member
Moderator
Joined
Sep 4, 2006
Messages
20,969
Not really any kind of brain case or skull. In fact the central brain is donut shaped with the esophagus running through the donut hole. The brain is located just under the eyes, the bag behind the eyes (the mantle) contains all the other body parts (gut, reproduction, elimination, etc.). When you feel around the head it does feel like there is some kind of cartilage but I have not dissected one to see if the tissue is actually thicker or different.
 
Joined
Jun 21, 2020
Messages
70
Not really any kind of brain case or skull. In fact the central brain is donut shaped with the esophagus running through the donut hole. The brain is located just under the eyes, the bag behind the eyes (the mantle) contains all the other body parts (gut, reproduction, elimination, etc.). When you feel around the head it does feel like there is some kind of cartilage but I have not dissected one to see if the tissue is actually thicker or different.
Thanks. Given their ability to squeeze through such miniscule openings, any references to a “brain case” (if it were of a rigid nature) didn’t really make sense. Could be just a bit of additional muscular “padding”, I suppose.
 
Joined
Jun 21, 2020
Messages
70
Thanks. Given their ability to squeeze through such miniscule openings, any references to a “brain case” (if it were of a rigid nature) didn’t really make sense. Could be just a bit of additional muscular “padding”, I suppose.
Are all the other organs rather loosely contained within a fluid-filled mantle, then, or are they confined within muscular “compartments”?
 

DWhatley

Kraken
Staff member
Moderator
Joined
Sep 4, 2006
Messages
20,969
Not quite sure what you are envisioning. Even though the mantle looks like a bag, all the interior plumbing is normally connected (although ink sacks are not exactly "normal" so the plumbing is octopus, not vertebrate)
 
Joined
Jun 21, 2020
Messages
70
One of the books mentioned the male inserting his reproductive arm into the female’s mantle, which kinda conjured up an image of everything being rather separated and jumbled within.
 

DWhatley

Kraken
Staff member
Moderator
Joined
Sep 4, 2006
Messages
20,969
The octopus mantle is attached to the head at the front of the animal where squid mantles are attached inside only so that they are open 360 degrees. I am not sure that we have actually fully figured out where the spermataphores (or the sperm once released) go once they are deposited. In some squids it appears that the spermataphores are darted into the mantle (rather than placed inside via an opening) and that they "make their way" to the "proper" location. The sperm is stored until it is used. For octopuses that can be up to an estimated 3 months (timing varies widely by species). They are definitely alien beings.

Here is a short octopus dissection. The animal was preserved and is dessicated but it gives you an idea of how it is put together, in particular she mentions the "closed" structure of the internals.

 
Joined
Jun 21, 2020
Messages
70
That was exactly what I wanted to see. I was THIS close to driving to the supermarket and seeing if I could buy one to dissect, but then I wouldn’t have known what I was looking at. THANK YOU!!!
 
Joined
Jun 21, 2020
Messages
70
I suppose I was envisioning more along the lines of how you described the squid mantle—open on all sides. May still give the supermarket a visit, now that I know what to look for.
 

Forum statistics

Threads
20,843
Messages
206,718
Members
8,457
Latest member
DaneMom6800

Monty Awards

TONMOCON IV (2011): Terri
TONMOCON V (2013): Jean
TONMOCON VI (2015): Taollan
TONMOCON VII (2018): ekocak


Top