to dry out during low tide periods. Bio-erosion Limpets are known to cause bio-erosion on sedimentary rocks by the formation of homescars and by ingesting tiny particles of rock through the action of feeding. C.Andrews & R.B.G. Williams in their research paper titled Limpet erosion of chalk shore platforms in southeast England from Oct 2000 estimate from the amount of calcium carbonate deposits in faeces of captive limpets, that an adult limpet will ingest around 4.9 g of chalk per year. Suggesting that limpets are on average responsible for 12% of the chalk platform erosion in areas that they frequent, potentially rising to 35% + in areas where the limpet population has reached its maximum. Naming The common name "limpet" also is applied to a number of not very closely related groups of sea snails and freshwater snails (aquatic gastropod mollusks). Thus the common name "limpet" has very little taxonomic significance in and of itself; the name is applied not only to true limpets (the Patellogastropoda), but also to all snails that have a simple shell that is broadly conical in shape, and either is not spirally coiled, or appears not to be coiled in the adult snail. In other words, the shell of all limpets is "patelliform", which means the shell is shaped more or less like the shell of most true limpets. The term "false limpets" is used for some (but not all) of these other groups that have a conical shell. Thus, the name limpet is used to describe various extremely diverse groups of gastropods that have independently evolved a shell of the same basic shape (see convergent evolution). And although the name "limpet" is given on the basis of a limpet-like or "patelliform" shell, the several groups of snails that have a shell of this type are not at all closely related to one another. Teeth Function and formation In order to obtain food, limpets rely on an organ called the radula, which contains iron-mineralized teeth. Although limpets contain over 100 rows of teeth, only the outermost 10 are used in feeding. These teeth form via matrix-mediated biomineralization, a cyclic process involving the delivery of iron minerals to reinforce a polymeric chitin matrix. Upon being fully mineralized, the teeth reposition themselves within the radula, allowing limpets to scrape off algae from rock surfaces. As limpet teeth wear out, they are subsequently degraded (occurring anywhere between 12