Magellanic spiral galaxies are (usually) dwarf galaxies which are classified as the type Sm (and SAm, SBm, SABm). They are galaxies with one single spiral arm, and are named after their prototype, the Large Magellanic Cloud, an SBm galaxy. They can be considered to be intermediate between dwarf spiral galaxies and irregular galaxies.
Type Sm and Im galaxies have also been categorized as irregular galaxies with some structure (type Irr-1). Sm galaxies are typically disrupted and asymmetric. dSm galaxies are dwarf spiral galaxies or dwarf irregular galaxies, depending on categorization scheme.
|Example||Type||Image||Information and Notes|
|NGC 5204||SAm||Satellite of Pinwheel Galaxy|
|NGC 4625||SABm||It has only one spiral arm. In ultraviolet it extends four times farther than in visible light.|
|NGC 4236||SBdm||In M81 Group|
|Large Magellanic Cloud||SBm||Prototype galaxy for this galaxy class, and satellite of Milky Way|
|Dwarf Magellanic Spirals|
|NGC 5474||dSm||Satellite of Pinwheel Galaxy|