Turtle Shells

Ada McVean: "Daily reminder that turtles are not 'inside' their shells. They *are* their shells."

Daily reminder that turtles are not “inside” their shells. They *are* their shells. pic.twitter.com/CS8UcDE3o2

— Ada McVean 🐢 (@AdaMcVean) April 21, 2020

McVean elaborates:

Quick guide: mollusk shells = exoskeleton (they can often leave them) veterbrate shells (turtle/tortoise) = endoskeleton (they can't leave them, it's part of their spine)