466 NATURAL HISTORY OF HAWAII. 



at the mouths of streams. The wi "''^ is found only in fresh water. It is 

 the largest species of the genus in the islands, being more than an inch in 

 diameter. It is black in color and the shell is curiously granular over the 

 surface. One species ''" commonly found at Waikiki is horn color, while a 

 second species 'J' from the same locality has distinct growth lines. The black 

 epidermis is marked with nimierous minute yellowish spots, sometimes scarcely 

 visible; the outer lip of the aperture is bluish in color. 



Turban Shells. 



The large family of turban shells,"- to which belong the typical turban 

 shells, •'^ the pheasant shells •'^ and the star shells,"^ is represented in Hawaii by 

 pei'haps a dozen and a half species. Not more than a third of that number 

 are liable to be collected, however. Only two species appear in the collection 

 of beach specimens before me from the shores of Oahu. The larger one "'^ is 

 brownish or white marbled with chestnut; the smaller one is dirty white 

 strongly tinged w-ith green and variously marked on the body whorl with dark 

 brown. The characteristics employed in descriptions of the species in this 

 family are confusing, and much skill is required in order to make the identifi- 

 cation of the species certain. 



Top Shells. 



Of the top shells,''' only two of tlie ten or a dozen species which have 

 been recorded from Hawaii occur in the little collection of shore shells that 

 serves as the basis of this brief account of the common moUusks of Hawaii. 

 Of these, the Hawaiian top shell ®* is by far the most common. It is a shallow- 

 water species occurring at Pearl Harbor, Hilo and elsewhere about the group 

 where slightly brackish water may be found. The second species "■' was col- 

 lected only at Kahana Bay and appears to be a rare form. 



Limpets. 



Several species of limpet-like shells may be easily collected from the rocks 

 between the tide-marks, or may be found cast up on the sand beaches along 

 the shores of all the islands. While the keyhole limpets '"^ are represented by 

 one or two species, they are by no means as common as the species belonging to 

 the old-world limpets,'^ from which they differ by having a small hole through 

 the apex of the shell. The families and species of this sub-order of conical, 

 cup-shaped shells are separated in the main by obscure and difficult character- 

 istics that render them almost beyond definite determination by amateur col- 

 lectors. Two species belonging to the keyhole limpets"- are occasionally col- 

 lected, especially at Hilo, and Honolulu harbor. 



To the old-world limpets belong the opihi '* of the natives. It is a favorite 

 food with the Hawaiians, and fine specimens may often be secured alive in the 



^' Neritina nranom. Tlie native n.ime hihiwai is applied to all the brackish and fresh water forms of 

 yerUinn. "" Neritina veapertina. "^ NeriUna eariosa. "- Turbinida. "Turbo. >" Pliasiniiella. 



0' Aatralium. <"' Turbo chrysoatomus. '^ Trochidce. "^ Trochus sandwiccnms. »» Troc/iKS sp. 



'0 Fissurellidcv. '» Patellidce. '^ Glilphis granifera and Subemarginula oblon<ia. 

 "•^ Helcioniscus exarotua. 



