On How Mollusks are Cooler Than Echinoderms (or anything else) Pt. 3: The Radula

In general, among Mollusks, the mouth opens into a buccal cavity. In most classes of Mollusks, the buccal cavity contains a tongue called the odontophore. The odontophore possess multiple rows of teeth called radula that chitonous and flexible. Among Mollusks the number of teeth can range from a few to over 100,000. The size, number, and arrangement of the radula also vary considerably and often used as diagnostic tool for distinguishing species. In some gastropods the radula is used in a rasping or conveyor belt fashion and be used to drill holes through hard parts of other organisms. The image above from here is from the whelk Busycon carica (Gmelin, 1791). Below is an Apple Snail in rasping material of the side of aquarium.

Below the fold is another way gastropods feed.

Feeding in Holothurians not so cool. Most are suspension or deposit feeders. Some species extend there nasty branched, mucus-covered tentacles into the water to trap particles. Those nasty mucus and dirt covered tentacles are then put into the mouth. Other species plow through the mud using their tentacles to selectively feed on particles. Apparently, they are also picky eaters.

Dr. M (1801 Posts)

Craig McClain is the Executive Director of the Lousiana University Marine Consortium. He has conducted deep-sea research for 20 years and published over 50 papers in the area. He has participated in and led dozens of oceanographic expeditions taken him to the Antarctic and the most remote regions of the Pacific and Atlantic. Craig’s research focuses on how energy drives the biology of marine invertebrates from individuals to ecosystems, specifically, seeking to uncover how organisms are adapted to different levels of carbon availability, i.e. food, and how this determines the kinds and number of species in different parts of the oceans. Additionally, Craig is obsessed with the size of things. Sometimes this translated into actually scientific research. Craig’s research has been featured on National Public Radio, Discovery Channel, Fox News, National Geographic and ABC News. In addition to his scientific research, Craig also advocates the need for scientists to connect with the public and is the founder and chief editor of the acclaimed Deep-Sea News (http://deepseanews.com/), a popular ocean-themed blog that has won numerous awards. His writing has been featured in Cosmos, Science Illustrated, American Scientist, Wired, Mental Floss, and the Open Lab: The Best Science Writing on the Web.

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