The Marble Cone
Conus marmoreus is the type species of the genus Conus, and therefore the species that defines the genus. Conus marmoreus is found from the Southern tip of India to Okinawa, and southeast to New Caledonia and Samoa. Conus marmoreus feeds on other snails, including other Conus. It is called a molluscivorous. When it attacks its prey, it sticks out its long white proboscis, and will typically sting the prey multiple times. The prey gets paralyzed and its muscles begin to relax irreversibly. Once the prey lies flaccid outside its shell, the snail can begin to devour it. The species is found in fairly shallow water (1-50 meters), typically on coral reef platforms or lagoon pinnacles, as well as in sand, under rocks or sea grass. This is an unusual cone snail in that it is quite active during the day, and not strictly nocturnal like most other Conus.
Some of the peptide toxins found in the venom of Conus marmoreus have been characterized; one of these is being developed as a potential drug for pain. Several other cone snails whose venoms have been characterized have components that have therapeutic promise.
Most marble cones look like the photograph shown above, but in a few localities, there are unusual variations. Perhaps the most striking are some shells of the marble cone from New Caledonia, where some Conus marmoreus lose their black coloration, and in some cases, can even be pure white.
Because this species shell has a striking pattern, it has been the subject of paintings, particularly in Holland in the 16th and 17th Century. Rembrandt tried making wood blocks of Conus marmoreus, but he forgot to reverse the handedness of the snail, and therefore the prints shows a snail whose body whorl rotates the wrong way. An example of Rembrandt’s etchings, which he was continually revising, is shown below.