438 NATIRAL HISTORY OF HAWAII. 



that reason. As many of them are scarcely an eighth of an inch in length, 

 they require that careful search and much patience be expended in collecting 

 them. 



Among the more conspicuous of the various families, not inchulcd in the 

 extensive divisions of the Acliatiiipllida. are the Sncciiicicke. There is hut 

 the single genus* in the family, with perhaps thirty species known from the 

 islands ; the larger number being found on the Island of Hawaii. They are 

 delicate thin-shelled mollusks with a slightly spiral shell, the last whorl of 

 which is large and flattened, giving the empty shell the appearance of a 

 twisted finger-nail. The ma.iority of the species prefer damp situations, usually 

 under luxuriant foliage, though there are species that vary their habitat 

 somewhat. Another family " with very fragile spiral shells is represented by 

 perhaps a dozen species of the genus LinnKva. At least half the known species 

 are from Oahu. The best representative of the genus is the small shell '" 

 found floating on the surface of the water in taro and rice ponds about Hono- 

 lulu. Other forms occur in the cool mountain water at high elevations ; a 

 horn-colored species ^^ found on the rocks beside the waterfalls at the head of 

 JIanoa Valley furnishing a good examjtle. Eriiiiia iiewcombia is the only 

 known Hawaiian species of this related genus; it was reported only from the 

 Hanalei river, on Kauai, until the author collected specimens from the Linia- 

 huli stream. 



A very minute cap-shaped shell '- found in various sti'eams on the under 

 side of decaying leaves, especially the leaves of kukui and hau, also belongs in 

 this group, although there is little in the shajie of the tiny paper-like shell to 

 suggest such a relationship. While they ai-e fairly common and are (|uite 

 generally distributed, on Oahu at least, they are very seldom seen even b,v 

 expert collectors. 



The conspicuous and abundant long spiral fresh-water shells common in 

 the lower portion of the streams on Kauai, Oahu, Maui and Molokai are sure 

 to belong to one family.^'' The six known species are all placed in one 

 genus. i-* The species''' with the entire surface roughened is the more widely 

 distributed, being taken on all of the islands mentioned. The smooth species i" 

 has so far been collected on Oahu and Kauai, but both species often occur 

 together in the same stream. 



Some .veai's ago the Chinese introduced an edible snail '" which has become 

 firmly established in the taro and rice ponds of Kauai, Oahu, Maui and ilolokai, 

 and doubtless on the other islands. Large specimens may be collected, often two 

 inches or more in length, but as a rule they are seldom so large. The.v are, 

 however, easily the largest species of land or fresh-water shells in the group 

 and belong t<i a family'^ without other representatives in the islaiuls. 



The small globular snails''' with short spires occui-ring in damp woods 

 have as many as a dozen or more known species. They arc the only repre- 

 sentatives of the opereulate shells in the land fauna ; but as the largest 



