Maxwellia gemma
A small murex snail with a fusiform, banded shell.
Maxwellia gemma, known as the gem murex, is a marine gastropod mollusc in the family Muricidae. Its fusiform shell ranges from 16 to 40 mm in length. The shell is off-white with reddish-brown to bluish-black spiral bands along the leading edge of each varix. It has a short, subacute conical spire with five convex whorls. The body whorl is broad and spindle-shaped. Each spire whorl bears six rounded varices; these are broader on the body whorl but thinner and curved back on the upper whorls and around the siphonal canal. The sutures between whorls are deep and crossed by the oblique varices. The aperture is porcelaneous white, oval, with a finely dentate outer lip. The siphonal canal is short, nearly closed, and curves left at the base; there is no anal canal. The inner aperture surface is rippled, matching the outer ribs, and the columella is smooth. This species occurs in the Pacific Ocean from California to central Baja California, Mexico, in rocky areas from the littoral zone to 55 m depth. It is often abundant on breakwaters and near bay entrances.
Quick Facts
- Genus
- Maxwellia (gastropod)
- Species
- gemma
Facts from the source article.
Lore & Background
The shell of Maxwellia gemma is fusiform and of moderate size, ranging from 16 mm to 40 mm in length. Its color is somewhat white, with spiral bands of reddish-brown to bluish-black on the leading edge of each varix. The shell has a rather short, subacute, conical spire composed of five convex whorls. The body whorl is broad and spindle-shaped. Each spire whorl contains six rounded varices that are broader on the body whorl but thinner and curved back on the stubby top whorls and around the siphonal canal. The sutures between the whorls are deep and crossed by the oblique varices. The porcelaneous white aperture is oval with a finely dentate outer lip. The siphonal canal is rather short, almost completely closed, and curved to the left at the base. There is no apparent anal canal. The inner surface of the aperture has a rippled form reflecting the ribs on the outer surface, and the columella is smooth.
Reader's Guide
Maxwellia gemma is distributed in the Pacific Ocean along California to Central Baja California, Mexico, inhabiting rocky areas from the littoral zone to depths of 55 m. It can often be found in great numbers on breakwaters and close to the entrances to bays. This species is a representative of the Muricidae family, commonly known as murex snails or rock snails. Its shell morphology, with six rounded varices per whorl and a short, curved siphonal canal, is characteristic of the group. The gem murex is a common component of the intertidal and shallow subtidal rocky fauna in its range, and its abundance on artificial structures such as breakwaters highlights its adaptability to modified coastal environments. The species does not have an anal canal, a feature that distinguishes it from some other muricids. Its smooth columella and porcelaneous white aperture with dentate outer lip are consistent features of the shell.
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