Muricidae

Muricidae, common name murex snails or rock snails, is a large and varied taxonomic family of small to large predatory sea snails. At least 1,000 species of muricids are known, and there are numerous subfamilies, although experts disagree about the subfamily divisions.

Many muricids have unusual shells which are considered attractive by shell collectors and by interior designers.Muricid shells are variably shaped, generally with a raised spire and strong sculpture with spiral ridges and often axial varices (typically three or more varices on each whorl), also frequently bearing spines, tubercles or blade-like processes. Periostracum is absent in this family. The aperture is variable in shape, may be ovate to more or less contracted, with a well marked anterior siphonal canal that may be very long. The shell's outer lip is often denticulate inside, sometimes with a tooth-like process on its margin. The columella is smoothish to weakly ridged. The operculum is corneous, of variable thickness, with the nucleus near the anterior end or at about midlength of the outer margin.

Many muricids have episodic growth, which means that the shell grows in spurts, remaining the same size for a while (during which time the varix develops) before rapidly growing to the next size stage. The result is the series of above mentioned varices on each whorl.Most species of muricids are carnivorous, active predators that feed on other gastropods, on bivalves, and on barnacles. The access to the soft parts of the prey is typically obtained by boring a hole through the shell by means of a softening secretion and the scraping action of the radula. Because of their carnivorous way of life, some species may be considered pests because they can cause considerable destruction both in exploited natural beds of bivalves, and also in farmed areas of commercial bivalves.

Muricids lay eggs in protective corneous capsules the size and shape of which vary with the species. Out of these capsules the crawling juveniles, or more rarely planktonic larvae, hatch.


source : http://en.wikipedia.org/wiki/Muricidae


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