Roper, Clyde F. E. Division of Molluscs, Smithsonian Institution, U.S. National Museum, Washington, DC.
- Links to Primary Literature
- Additional Readings
An order of the class Cephalopoda (subclass Coleoidea) including the cuttlefishes (Sepia), the bobtail squids (Sepiola), and the ram's-horn squid (Spirula). The group is characterized by an internal shell that is calcareous and broad with closely packed laminate chambers (the cuttlebones of cuttlefishes); calcareous, cylindrical, and coiled with about 40 subspherical chambers (the ram's-horn shell of Spirula); chitinous and rod- or bladelike (the gladius of bobtail squids); or absent. The mouth is surrounded by ten appendages (eight arms and two longer tentacles) that bear suckers with chitinous rings. The tentacles are contractile and retractile into pockets at their bases (see illustration).
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Contributors include more than 9000 highly qualified scientists and 43 Nobel Prize winners.
MORE THAN 8700 articles covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 19,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information