To GASTROPODA start

	53a	(44)	Shell planular or disc-shaped, with sunken spire, reddish brown in color. Operculum absent ~ Subclass PULMONATA Family PLANORBIDAE Planorbella duryi Wetherby
	53b		Shell with a raised spire, globose to conical. Operculum present or absent	[54]
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	54a	(53)	Operculum absent. { Shell oliviform, conical, or horn-shaped ~ Subclass PULMONATA	[55]
	54b		Operculum present. { Shell conical, globose or subglobose	[60]
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	Figure 1. Typical "pond snail" (PHYSIDAE) showing sinistral coiling and filiform tentacles
	55a	(54)	Shell oliviform to elongate oliviform, sinistral. Mantle edge digitate in front and behind. Tentacles long and filiform (Fig. 1). Ponds and pools in slow-flowing streams. Pond snail (very common) ~ Family PHYSIDAE Physa sp.
	55b		Shell conical to horn-shaped, dextral or sinistral. Mantle margin without papillae or digitations. Tentacles short and triangular ~ Family LYMNAEIDAE	[56]
			   Key to Family Lymnaeidae
	56a	(55)	Shell dextral, extremely low-spired, nerite-like	[46]
	56b		Shell sinistral or dextral, spire moderate	[57]
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	57a	(56)	Shell sinistral, with medium high spire Pseudisidora producta Mighels
	57b		Shell dextral	[58]
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	58a	(57)	Shell weakly globose, tending to rhomboidal form, spire small. Uncommon; in quiet fresh waters Galba viridis Quoy & Gaimard Lymnaea rubella Lea
	58b		Body whorl greatly expanded at aperture, spire small but elongate (shell horn-shaped). Common in lowlands; quiet fresh waters Pseudosuccinea columella Say
	60a	(54)	Operculum with concentric growth rings around nucleus. { Shell medium to large (12-75 mm) ~ Superfamily VIVIPAROIDEA	[61]
	60b		Operculum spiral, consisting of two or more rapidly increasing whorls. { Shell usually small to medium (2-20 mm)	[65]
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	61a	(60)	Umbilicus of shell perforated or broadly open. Spire depressed, much less than height of large aperture. Eggs deposited above water in dry clusters on stems, etc. or in water in gelatinous clusters. Males with penis at anterior right corner of mantle cavity. Apple snails ~ Family AMPULLARIIDAE	[62]
	61b		Umbilicus of shell closed. Spire usually about equal to or greater than height of aperture. Females with live embryos in brood pouch in mantle; males with right eye stalk modified as a penis. Streams ~ Family VIVIPARIDAE Cipangopaludina chinensis (Reeve)
			   Key to Family Ampullariidae
	62a	(61)	Operculum calcareous Pila conica Gray
	62b		Operculum corneous	[63]
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	63a	(62)	Whorls of spire scalariform (steplike with nearly flat shoulders and deep sutures); apical whorls raised to form a point on top of spire. Adult shell about 40-60 mm high. Spiketopped applesnail. Uncommon Pomacea bridgesi (Reeve) [Note C]
	63b		Whorls of spire strongly arched or rounded, not or hardly at all stepped. Adult shell 40 - 70 mm high	[64]
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	64a	(63)	Whorls of spire with indented sutures forming an angle less than 90o. Adult shell about 40-70 mm high. Applesnail. Common Pomacea canaliculata (Lam.) [Note C]
	64b		Whorls of spire with almost flat, forming an angle greater than 90o. Adult shell about 45-65 mm high. Applesnail. Uncommon Pomacea paludosa (Say) [Note C]
	65a	(60)	Conical shell with spiral cords and spiral striae, color usually gray, brown, yellow or rose with brown blotches. Aperture broadly oval, without siphonal notches. Quiet marine waters and estuaries, living above water line ~ Family LITTORINIDAE Littorina scabra (L.)
	65b		Snail otherwise	[Note B]

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Note B:
Your identification is leading to a group with no fresh or brackish water representatives in Hawai`i. The identification may be correct for the location where you made the collection or observation (e.g., near the ocean), but the species is marine and may not be covered in the key. If the collection was made in freshwater, you should back up several couplets and confirm your decisions.

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Note C:
An introduced pest species of special concern. Specimens should be kept in an aquarium, euthanized, or preserved for study. DO NOT RELEASE back into the wild.