Maxwellia gemma
Encyclopedia
Maxwellia gemma, common name : the gem murex, is a species
of sea snail
, a marine gastropod mollusk in the family
Muricidae
, the murex snails or rock snails.
shell is of moderate size and its length varies between 16 mm and 40 mm. The color of the shell is somewhat white with spiral bands with a reddish-brown to bluish-black color on the leading edge of each varix. The shell has a rather short, subacute, conical spire. There are five convex whorls
. The body whorl
is broad and spindle-shaped. Each spire whorl contains six rounded varices that are broader at the body whorl
, but thinner and curved back at 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
has an oval shape and has 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 form of the ribs at the outer surface. The columella
is smooth.
to Central Baja California
, Mexico in rocky areas from the littoral zone to depths of 55 m. It can often be found in great numbers on breakwater
s and close to the entrances to bays.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of sea snail
Sea snail
Sea snail is a common name for those snails that normally live in saltwater, marine gastropod molluscs....
, a marine gastropod mollusk in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Muricidae
Muricidae
Muricidae, common name murex snails or rock snails, is a large and varied taxonomic family of small to large predatory sea snails. With approximately 1,600 living species the Muricidae represent almost 10% of the Neogastropoda. Additionally, 1,200 fossil species have been recognised...
, the murex snails or rock snails.
Description
The fusiformFusiform
Fusiform means having a spindle-like shape that is wide in the middle and tapers at both ends.* Aneurysms can be classified as saccular or fusiform...
shell is of moderate size and its length varies between 16 mm and 40 mm. The color of the shell is somewhat white with spiral bands with a reddish-brown to bluish-black color on the leading edge of each varix. The shell has a rather short, subacute, conical spire. There are five convex whorls
Whorl (mollusc)
A whorl is a single, complete 360° revolution or turn in the spiral growth of a mollusc shell. A spiral configuration of the shell is found in of numerous gastropods, but it is also found in shelled cephalopods including Nautilus, Spirula and the large extinct subclass of cephalopods known as the...
. The body whorl
Body whorl
Body whorl is part of the morphology of a coiled gastropod mollusk.- In gastropods :In gastropods, the body whorl, or last whorl, is the most recently-formed and largest whorl of a spiral or helical shell, terminating in the aperture...
is broad and spindle-shaped. Each spire whorl contains six rounded varices that are broader at the body whorl
Body whorl
Body whorl is part of the morphology of a coiled gastropod mollusk.- In gastropods :In gastropods, the body whorl, or last whorl, is the most recently-formed and largest whorl of a spiral or helical shell, terminating in the aperture...
, but thinner and curved back at the stubby,top whorls and around the siphonal canal
Siphonal canal
Some sea marine gastropods have a soft tubular anterior extension of the mantle called a siphon through which water is drawn into the mantle cavity and over the gill and which serves as a chemoreceptor to locate food. In many carnivorous snails, where the siphon is particularly long, the structure...
. The sutures between the whorls are deep and crossed by the oblique varices. The porcelaneous white aperture
Aperture (mollusc)
The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where part of the body of the animal emerges for locomotion, feeding, etc....
has an oval shape and has 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 form of the ribs at the outer surface. The columella
Columella
Lucius Junius Moderatus Columella is the most important writer on agriculture of the Roman empire. Little is known of his life. He was probably born in Gades , possibly of Roman parents. After a career in the army , he took up farming...
is smooth.
Distribution
This species is distributed in the Pacific Ocean along CaliforniaCalifornia
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
to Central Baja California
Baja California
Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...
, Mexico in rocky areas from the littoral zone to depths of 55 m. It can often be found in great numbers on breakwater
Breakwater
Breakwater may refer to:* Breakwater , a structure for protecting a beach or harbour* Breakwater, Victoria, a suburb of Geelong, Victoria, Australia* Breakwater , a funk and soul band from the 1970s...
s and close to the entrances to bays.