I didn't notice. Whoops. Although they're not cartilaginous either except for their braincase.
Yup, got it, please refer to edit. I realize that you have an occasionally insufferable need to be right, and I've tried to be pretty nice and civil to you, but you're getting on my last nerve and if I have to mute you by god I will fucking happily do so. I swear when the cuttlefish poem goes live I am going to post it here under the title "Poem Wherein Ref Claims Cuttlefish Are Cartilaginous But Don't Worry Guys She's Lying". Clearly there is some difficulty with understanding artistic language and poetic license here; clearly we must confine ourselves to the realm of facts, and clearly if we write anything that departs from absolute, black-and-white fact it will be misinterpreted and oh, yes, corrected. By those who are our betters, of course. Because who else could they be?
Sometimes it's nice to leave a trail of art behind us, revising as new information either becomes available or is found out by the artist: Mass of Incandescent gas? Or miasma of incandescent plasma? But to the larger point I think it's a fool that points out the factual fallibility of a poem. Often language and terminology are used evocatively, such is my guess with the "cuttlefish."