last week I saw the dissection of a squid. The hearts are really small, more like a bit of snot, then a pumping organ... strange experience, fascinating. there are indeed three of them, one has some sort of a square-like shape. the other two are like fat cookies... The veins are very hard to see, the blood is invisible, you can see right through it. This is a problem for me, since I make the veins in wax. Still trying to figure out how to show this snot-like structures in stone! I think I'll use Belgian Royal Marble. It has lots of veins and is very difficult to carve in. But beautiful!
The yellow parts on the photo below show the gill heart (with the gills in black ink colored in the back) and the systemic heart in light yellow in the middle.
The very thin white kind of structure running down is a vein..
I was able to film the dissection at the university of Ghent. Sophie gave me a very comprehensive explanation about the circulatory system of the animal. This is only a small part of the dissection. With many thanks!!!