Cul-de-Sac Snails

Snails, as a rule, grow up in a rather predictable pattern. As soon as they form their shells, they spend the rest of their development growing bigger and expanding these shells—but these shells just go round and round in circles. There are a few notable exceptions, such as cowries and tube snails, but in general, even these retain some sort of souvenir of their spiral stage.

There is one family of snails, however, that follow an entirely different course of life. When still quite young, they reject the onward spiral pattern—actually leaving it behind. Instead, they go for the (almost) straight and narrow. Yet even by striking out on a path of their own, they never attain much greatness. In fact, they end up on a dead-end street, a cul-de-sac existence.

The snails are members of the family Caecidae, which range throughout the world, in warm and temperate waters. They begin life with regular spiral shells, but soon change to a tube form. As the tube proceeds, they make a plug at the far end of the tube and the original spiral portion is broken off, never to be returned to again. The final result is a slightly curved cylinder, plugged up on one end and open on the other.

The exact number of species within this family is hard to determine. Part of the problem is that all of these snails are extremely small, usually less than 1/4 inch in length. To make matters even more complicated, however, is the fact that a single species can look quite different during the different stages of its development. So if a biologist discovered a fully formed adult, it would have been classified one way under a certain name. But then if another biologist found the same type of snail, only in its juvenile stage that still had some of its spiral, well since it looks like an entirely different animal, it probably ended up with a whole other name. And on and on, through all the intermediate stages as well. One of California’s more common species has been so plagued in this regard that it has been dubbed “Many-Named.”

In general, however, there has been consistency at least as to what genus these snails should be classified in, or in Caecum. Now, to people familiar with medical terms and/or anatomy, this term may seem rather surprising, because, yes, it is exactly the same word as a part of the gut. (In American spelling the variation “cecum” if often used.) It is not just a coincidence or somebody’s warped sense of humor that accounts for this. “Caecum” is from Latin and basically means “blind-ended pouch” or “cul-de-sac.” And while there is such a part to be found in a person’s intestines, it is also an accurate description of these little snails’ shells. A close look at such a shell will reconfirm this.

However, any person who wants to locate some of these tiny shells may at first feel that they are facing not only a “dead-end street” but also an insurmountable roadblock. How can anyone find something so small? Well, it isn’t that impossible, since at least some species are quite common—even abundant—and live in areas people often frequent as well.

The California Ceacum Snail (Caecum californicum), although only about 1/8 of an inch long, can be found in large numbers in tidepools and around eelgrass, even in the subtidal realms of divers. It ranges from Monterey south into Mexico.

The even smaller Caecum orcutti has a fairly similar range but is found a bit higher in the tidal zone, on the underside of rocks. The Many-Named Caecum (Caecum crebricinctum), a relative giant at 1/4 inch in length, is only found below the tidal zone, in the gravel around kelp beds, from British Colombia to Baja.

Of course, even when a diver or beachcomber finds a large number of cul-de-sac snails, it may be hard to really see what they are. They are so small that they may just look like a bunch of spilled grains of rice. Those dreaded bifocal lenses on the masks of the “over forty” crowd may not help that much.

To fully appreciate the beauty of these shells, a magnifying glass—or even a microscope—is typically employed. With these tools, C. orcuttiís smooth surface and tan color can be seen, and the Many-Named fine rings and mottled color can be distinguished from the California Caecum’s accordion-style rings and plain brown color.

It is on account of their beauty and uniqueness, that these snails are actively sought by collectors. Truly, anyone who is interested in the unusual will find these tiny snails a wonderful outlet for their curiosity.

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