Home > Invertebrates > Shells > Turbinate Shells

Updated 4/22/2026

Subclass Vestigastropoda

Order Trochida

Trochids are herbivorous or detritivorous snails with stout conical or inflated shells, some having a mother-of-pearl interior.  This large group is well-represented in warm and cool seas from tidepools to the deep sea.  Families are organized by anatomical features such as the operculum, a thick calcareous ‘cat’s eye’ in turbans, or a thin protein-based operculum in tops.  Most local species measure less than half an inch (12 mm), falling into the micromollusk category, and Hawaiians on Ni’ihau weave exquisite lei including tiny kahelelani shells.

 

Family Trochidae

Top Snails

Tops shells are herbivorous snails with a thin yellow-brown operculum.  The interior is lined with mother-of-pearl. 

INDO-PACIFIC / HAWAII

Trochus intextus

HAWAIIAN or WOVEN TOP   HĀ‘UPU

 

 Alcyna ocellata

OCELLATED TOP
Calliotrochus marmoreus

MARBLED TOP    KAHELELANI

 

 Synaptocochlea concinna

PRETTY EAR SHELL

INDO-PACIFIC

Clanculus margaritarius

BEAUTIFUL TOP

 

 Trochus radiatus

RADIATE TOP

 
Monilea belcheri

BELCHER'S TOP

 

  

 

  

Family Calliostomatidae

Shells have a chitinous operculum and until recently this group included within Family Trochidae.  None occur in Hawaii.

NORTHEAST PACIFIC

Calliostoma ligatum

WESTERN RIBBED or BLUE TOP SHELL

 

 Calliostoma annlatum

BLUE-RING TOP SHELL

Family Chilodontidae

Toothed Top Shells

Micromollusks formerly included within Family Trochidae.  They have prominent teeth on the lower columella, a chitinous operculum, and pearly interior.

INDO-PACIFIC / HAWAII

Herpetopoma gemmatum

GEM TOP

 

 Herpetopoma gemmatum

GEM TOP

 

 

  

Family Tegulidae

INDO-PACIFIC

Tectus pyramis

PYRAMID or GREEN TOP SHELL

 

 Rochia nilotica

PEARLY TOP SHELL
   

CALIFORNIA

Norrisia norrisi

NORRIS' TOP SHELL

 

Family Turbinidae

Turbans

Turbans are herbivorous snails that possess a thick calcareous operculum called a 'cat's eye'.  The interior is lined with mother-of-pearl.

HAWAII - ENDEMIC

Turbo sandwicensis

HAWAIIAN TURBAN   KĀMOA

 

 

INDO-PACIFIC

Turbo petholatus

TAPESTRY TURBAN

 

 

 

CALIFORNIA

Megastraea undosa

WAVY TURBAN

 

Family Colloniidae

These herbivorous micromollusks were formerly included within Family Turbinidae.  They have a calcareous operculum and pearly or white interior.

INDO-PACIFIC / HAWAII

Microcollonia candida

CANDID TURBAN

 

 Microcollonia rubricincta

RED-BANDED TURBAN

 
Homalopoma verruca

WARTY TURBAN    KAHELELANI

 

  

 

Family Phasianellidae

Pheasant Shells

Tiny herbivorous snails associated with seaweed.  Most are so fragile and tiny that they go unnoticed on reefs and beaches.  The aperture lacks teeth and the operculum is calcareous.

INDO-PACIFIC / HAWAII

Hiloa variabilis

VARIABLE PHEASANT SHELL

 

  
   

Order Caenogastropoda

This order contains a large number of families with the common trait of being herbivorous or detritivorous.  The few shells included in this section for convenience have shapes similar to those within Order Trochacea.

Superfamily Campaniloidea

Family Plesiotrochidae

INDO-PACIFIC / HAWAII

Plesiotrochus unicinctus

SINGLE-BANDED TOP

 
   

Superfamily Cerithioidea

Family Modulidae

Modulids are herbivorous snails that possess a strong peg-like tooth on the columella.  One species occurs in Hawaii.

INDO-WEST PACIFIC / HAWAII

Indomodulus tectum

KNOBBY SNAIL

 

Family Planaxidae

Small herbivorous snails that inhabit rock reefs and tidepools.

HAWAII - ENDEMIC

Fossarus cumingii

CUMING'S FOSSARUS

 

Family Vanikoridae

Vanikoro snails

Vanikorids are small carnivorous snails rarely encountered alive in rubble or dead coral.  They have a turbinate shell with an umbilicus, thin operculum, and hairy periostracum.  Four species occur in Hawaii.

 INDO-PACIFIC / HAWAII

Vanikoro acuta

ACUTE VANIKORO

 

 Vanikoro cancellata

LATTICE VANIKORO