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The radula (US: / ˈ r æ dʒ ʊ l ə /; pl.: radulae or radulas) [1] is an anatomical structure used by mollusks for feeding, sometimes compared to a tongue. [2] It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters the esophagus .
The buccal mass is the first part of the digestive system, and consists of the mouth and pharynx. The mouth includes a radula, and in most cases, also a pair of jaws. The pharynx can be very large, especially in carnivorous species. Many carnivorous species have developed a proboscis, containing the oral cavity, radula, and part of the ...
The subradular organ is a sensory organ below the grinding mouthparts of some molluscs, specifically the chitons. [1] This organ is involved in chemoreception - that is, in judging the nature of food or the substratum. In this sense, it can be considered a 'smell' or 'taste' organ; food is sensed before each stroke of the radula. [1]
The radula is used to scrape microscopic algae off the substratum. The mouth cavity itself is lined with chitin and is associated with a pair of salivary glands. Two sacs open from the back of the mouth, one containing the radula, and the other containing a protrusible sensory subradular organ that is pressed against the substratum to taste for ...
In 2005, Philippe Bouchet and Jean-Pierre Rocroi made sweeping changes in the systematics, resulting in the Bouchet & Rocroi taxonomy, which is a step closer to the evolutionary history of the phylum. [3] [47] The Bouchet & Rocroi classification system is based partly on the older systems of classification, and partly on new cladistic research.
The radula is wide and distinctively has nine teeth. The mouth consists of a parrot-like beak made up of two interlocking jaws capable of ripping the animal's food— mostly crustaceans— from the rocks to which they are attached.
The hyponome or siphon is the organ used by cephalopods to expel water, a function that produces a locomotive force. The hyponome developed from the foot of the molluscan ancestor. [14] Water enters the mantle cavity around the sides of the funnel, and subsequent contraction of the hyponome expands and then contracts, expelling a jet of water.
The respiratory system of gastropods varies greatly in form. These variations were once used as a basis for dividing the group into subclasses. The majority of marine gastropods breathe through a single gill, supplied with oxygen by a current of water through the mantle cavity.