Achatinella bulimoides is a species

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 air-breathing land 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...

, a terrestrial

Terrestrial animal

Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...

 pulmonate gastropod mollusk in the family Achatinellidae

Achatinellidae

Achatinellidae is a family of tropical air-breathing land snails, terrestrial pulmonate gastropod mollusks in the superfamily Achatinelloidea.- Taxonomy :...

. This species is endemic to Hawaii

Hawaii

Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...

.

Shell description

The dextral or sinistral shell

Gastropod shell

The gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...

 is ovate-oblong and subventricose. The shell has 6¼ 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 shell is similar in form to Achatinella livida

Achatinella livida

† Achatinella livida was a species of air-breathing land snail, a terrestrial pulmonate gastropod mollusk in the family Achatinellidae. This species was endemic to Hawaii....

, but the 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...

 is less thickened and more pointed at the apex

Apex (mollusc)

Apex is an anatomical term for the tip of the mollusc shell of a gastropod, scaphopod, or cephalopod mollusc.-Gastropods:The word "apex" is most often used to mean the tip of the spire of the shell of a gastropod...

. The color is whitish with chestnut bands, and the apex is pale brown. The ground-color, in some specimens, is pale chestnut or ferruginous, banded with darker
shades. Other specimens are pure white. The 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....

 is white. The suture is scarcely if at all margined by a groove.

The height of the shell is 21.3 mm. The width of the shell is 11.8 mm.

Achatinella rosea

Achatinella rosea Swainson, 1828 is a variety of Achatinella bulimoides. Its sinistral shell is a pale, rose color, with two obsolete white bands. The shell has 6⅓ whorls. The margin of the lip and columella are of a deeper rose-color, and the aperture white. It should be observed that the subsutural groove is very distinct. The height of the shell is 22.3 mm. The width of the shell is 13.5 mm.