1. The ink sac is pear-shaped, with a silvery blue-green outer layer. 2. Like many Parker fountain pens, the 180 had a flexible ink sac reservoir. 3. The squid can also secrete bioluminescent mucous from glands near the ink sac . 4. Like many deep-sea cephalopods, the vampire squid lacks ink sacs . 5. It employs the two defensive mechanisms typical of all octopuses : ink sacs and camouflage. 6. She also discovered that belemnite fossils contained fossilised ink sacs like those of modern cephalopods. 7. Cirrate octopuses are noteworthy for lacking ink sacs . 8. In the sandbox game " Minecraft ", squids are passive, non-playable characters that carry obtainable ink sacs . 9. The ink sac contains a dumbbell-shaped photophore. 10. The Sheaffer " Snorkel " system filled the ink sac through a retractable tube above and behind the pen point.