Shells

Snakes and Snail “Handedness”

As discussed previously in this blog, most snail species coil to the right (dextral), and a few, such as the local Lightning Whelk, coil to the left (sinistral). In a few species of land snails, however, there seems to be as many dextral individuals as there are sinistral ones. Switch gears to snail-eating snakes: As their common name suggests, Southeast Asian snail-eating snakes in the genus Pareas evolved to prey on snails, and do it by initially biting onto the outer rim (the “outer lip”) of

Nature’s Iron-based Shell Dye

Did you ever wonder why some shells on the beach are abnormally dark-gray, bluish, or almost black? They are not dark to begin with: The right valve of a Southern Quahog, Mercenaria campechiensis, on left, acquired its dark, bluish hues after being buried in sand or mud for some time (compare to “normal” color valve on right.) In sand or mud with levels of oxygen below normal (hypoxia) or where oxygen is completely lacking (anoxia), trace amounts of iron in the shell will combine with sulfur to

Shell of the Week: The Exquisite False Dial

Spirolaxis centrifuga (Monterosato, 1890) is a delicate and truly attractive species of the sundial snail family Architectonicidae. The species is found in deeper water in the western and eastern Atlantic, and may grow to about 5 mm (0.2 inch) in diameter. The shell is open-coiled, with successive whorls (shell “turns”) not touching each other, yet maintaining regular, proportional distances from the neighboring whorls. Gastropods from other families make open-coiled shells; they are all very el

New Jeweled Top Snails!

Our Aquarium Curator, Rebecca Mensch, just received a number of Jeweled Top Snails, Calliostoma annulatum (Lightfoot, 1786), AKA Purple-Ringed Top Snail, for display. This is a shallow- and cold-water gastropod from the West Coast of North America, found from Baja California, México, to Alaska. Jeweled Top Snails are normally associated with the large fronds of Giant Kelp seaweed Macrocystis pyrifera. This paragraph about the species, quoted from the Monterey Bay Aquarium website, explains its m

Striking Open-coiled Snails

The Exquisite False Dial, Spirolaxis centrifuga (Monterosato, 1890) is a delicate and truly attractive species of the sundial snail family Architectonicidae. The species lives in the eastern and western Atlantic Ocean, reaching about 5 mm* in diameter.As the photo above shows, the Exquisite False Dial shell is normally open-coiled, with successive whorls** not touching each other, yet maintaining regular, proportional distances from the adjacent whorls. Other gastropods with open-coiling are, f

More Additions to Collection Catalog Portal

Once again, a reminder about our collection catalog and its web portal, which allows you to search for our collection records online. The web portal, or online interface, now includes 2,225 composite images of mollusks and shells from Florida and the Bahamas. The Museum’s Digital Imaging Project is funded through a 2-year grant from the Institute of Museum and Library Services, under its Museums for America initiative.The acquisition, posting, and archival of images follows the latest standards

Is Shell Size Relative?

To the way a picture is taken, yes, it can be. Smart phone cameras, combined with a multitude of social media and online platforms, turned photography into a global phenomenon. Anyone can shoot and post, with the potential for hundreds or thousands of viewers to any single image, at any time. The selfie is probably the most popular kind of phone photography, for obvious reasons. Yet, one of the problems with selfies is unwanted distortion: the selfie-person gets a big nose, jutting chin, small e

Endangered Cuban Painted Snails

A recent feature in National Geographic online discusses the threats and pressures affecting the six species of Cuban land snail of the genus Polymita, commonly known as “painted snails." These species are arboreal (trees dwellers), and endemic (living only in that area) to Cuba. Many of their local populations were destroyed, initially by deforestation for agricultural uses, and are endangered by predation by invasive species and climate change. And their intrinsic beauty makes them serious can

Shell of the Week: The Atlantic Jewel Box

Pseudochama cristella (Lamarck, 1819) is a bivalve that lives permanently attached to hard surfaces such as other shells, coral rock, and even lost boat lines. The species may grow to 75 mm (about 3 inches), but is usually much smaller locally. The shell sculpture is variable, usually variations around the theme of 20–30 scaly radial ribs. The Atlantic Jewel Box is also known as the Left-handed Jewel Box; members of the jewel-box genus Chama are attached by their left valve, but species of Pseud

What Are Ridges, Varices, Spines?

Some of the most attractive shells of marine snails are distinguished by remarkable sculptures such as ridges, varices, and spines. Take, for instance, the Venus Comb Murex, with its rows of needle-like spines; the sturdy, keel-like varices of an Angular Triton; or the blade-like varices of a Maple Leaf Triton. These sculptures are built by the snail at recurring intervals. Their positions on the shell, outline, and structure define general shell shapes that may, among other advantages to the sn