Cystiscinae are a taxonomic subfamily of minute sea snail

Snail

Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...

s. These are marine

Marine (ocean)

Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...

 gastropod mollusks or micromollusk

Micromollusk

A micromollusk is a descriptive term for a shelled mollusk which is extremely small, even at full adult size. The word is usually, but not exclusively, applied to marine mollusks, although in addition, numerous species of land snails and freshwater mollusks also reach adult size at very small...

s in the family Cystiscidae

Cystiscidae

Cystiscidae is a taxonomic family of minute sea snails, marine gastropod mollusks or micromollusks.- Description :The shell is minute to large, either white, uniformly colored, or patterned; the surface is smooth, sculptured, or axially costate; the spire is flat to immersed, or low to tall; the...

, and the clade Neogastropoda

Neogastropoda

Neogastropoda is an unranked taxonomic clade of sea snails, marine gastropod mollusks. For many years prior to 2005 Neogastropoda was an order.- Description :...

.

Diagnosis

Shell minute to small, white; spire

Spire (mollusc)

A spire is a descriptive term for part of the coiled shell of mollusks. The word is a convenient aid in describing shells, but it does not refer to a very precise part of shell anatomy: the spire consists of all of the whorls except for the body whorl...

 immersed to low; surface smooth or axially costate; lip thickned, smooth or denticulate; external varix

Varix (mollusc)

A varix is an anatomical feature of the shell of certain sea snails, marine gastropod molluscs.It is a thickened axial ridge in the shell of some families of gastropods. A varix is located at intervals around the whorl, and is formed by considerable thickening of the outer lip at a resting stage...

 absent; siphonal notch absent; posterior notch absent; columella multiplicate, with combined total of usually 2 to 8 plications plus parietal lirae; internal whorl

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...

s cystiscid type. Animal mantle

Mantle (mollusc)

The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself.In many, but by no means all, species of molluscs, the epidermis of the mantle secretes...

 smooth, at least partially extending over external shell surface. Internal anatomy unknown.

Genera

Genera within the subfamily Cystiscinae are as follows:

• † Topaginella
  Topaginella
  Topaginella is a genus of minute fossil sea snails, marine gastropod mollusks in the family Cystiscidae. Like all of the related genera, this are sometimes still classified in the family Marginellidae.This genus is extinct.-Shell description :...
  
  Laseron, 1857
• Cystiscus
  Cystiscus
  Cystiscus is a taxonomic genus of minute sea snails, marine gastropod mollusks or micromollusks.This genus was placed in the family Cystiscidae by Coovert and Coovert, 1995...
  
  Stimpson, 1865
• Crithe
  Crithe
  Crithe is a genus of minute sea snails, marine gastropod mollusks or micromollusks in the family Cystiscidae. This genus is sometimes still placed within the Marginellidae....
  
  Gould, 1860
• Extra
  Extra extra
  Extra extra or Marginella extra is a species of minute sea snail, a marine gastropod mollusk or micromollusk in the family Cystiscidae. Some malacologists place this genus more simply in the family Marginellidae.- Taxonomy :...
  
  Jousseaume, 1894
• Intelcystiscus
  Intelcystiscus
  Intelcystiscus is a genus of minute sea snail, a marine gastropod mollusc or micromollusc in the family Cystiscidae.- Species:Species within the genus Intelcystiscus include:* Intelcystiscus coyi Espinosa & Ortea, 2002...
  
  Ortea & Espinosa, 2001
• Inbiocystiscus
  Inbiocystiscus
  Inbiocystiscus is a genus of minute sea snail, a marine gastropod mollusc in the family Cystiscidae.- Species:Species within the genus Inbiocystiscus include:* Inbiocystiscus gamezi Ortea & Espinosa, 2001 - type species...
  
  Ortea & Espinosa, 2001
• Ticocystiscus
  Ticocystiscus
  Ticocystiscus is a genus of minute sea snail, a marine gastropod mollusc in the family Cystiscidae.This genus, and indeed all the genera in the family, were previously and sometimes still are, placed in the family Marginellidae....
  
  Espinosa & Ortea, 2002