Diagnosis. Shells of Mitromorpha (Mitrolumna) are of small size (maximum length ca. 10 mm), robust, fusiform, biconic. The sculpture consists prevalently of spiral cords, frequently vanishing on the periphery. Axial ribs present especially on the first teleconch whorls. Growth lines somehow lamellose visible over the entire surface. Anal sinus shallow. All species studied herein have a paucispiral protoconch, indicating a non-planktotrophic development, shiny and sculptured by sparse microgranules. Adults develop two columellar folds, of which the posterior is often stronger. Inner side of the outer lip with a series of denticles. Siphonal canal short and wide. Coloration varying, from monochrome, to patterned with blotches, flammulae or bands.

The shells of the genus Mitromorpha are usually small, biconic and up to 20 mm. in height, although fossil species may reach 30 mm (e.g. Clinomitra rovasendae Bellardi, 1889). The body whorl takes up most of the total shell height. The sculpture is made up predominantly of spiral chords, but sometimes, axial folds or ribbing, especially on the first teleoconch whorls are also present. A shallow to medium sinus is present at the top of the outer lip. Most of the species possess a very similar protoconch, shell shape and sculpture, even from very distantly separated regions and are sometimes difficult to separate. For these reasons, a few names already in use could turn out to be synonymous, whilst there are a few others present in collections, which have been erroneously assigned. There is also a good number of others which are still undescribed.

Important diagnostic species characteristics include:
1) The number of spiral chords, especially on the penultimate whorl, above the aperture and which is fairly constant, unless the shell has undergone severe damage and repair (a common feature with shells of this genus). The number of these spiral chords usually increase by interpolation, by one, two or three at every subsequent whorl.
2) The presence, absence or extent of axial ribbing,
3) The type of protoconch. Surprisingly, this feature is not very variable in size and form for various different species of the subgenus Mitrolumna which have a world wide distribution. A few species demonstrate faint punctate spiral striae on the protoconch whorls.
4) The presence (or absence) of two columellar folds or pleats.
5) The size of shell for a particular number of teleoconch whorls.
6) The presence and type of colour bands, patterns or flammules on the shell surface. Although these may have different hues, they are usually very constant for a particular species.
7) The animal's colouration.
8) The radula

Shell small, somewhat elongate and biconic, with a globose nucleus; aperture scarcely or not at all notched behind; columella nearly straight, generally having faint vestiges of oblique plaits, which do not extend far into the shell; surface sculptured.