438 NATURAL HIST(3RY 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 included in the 

 extensive divisions of the AcJiati)iellidce, are the Sticcineidce. There is but 

 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 majority 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 Limnaa. 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 

 Manoa Valley furnishing a good example. Eriinta neiccomhia 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 Lima- 

 huli stream. 



A very minute cap-shaped shelP- found in various streams 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 shape of the tiny paper-like shell to 

 suggest such a relationship. While tliey are fairly common and are quite 

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

 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. ^^ The species ^^ wnth 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 years ago the Chinese introduced an edible snail ^' which has become 

 firmly established in the taro and rice ponds of Kauai, Oahu, ]\Iaui and ^lolokai, 

 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. They are, 

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

 and belong to a family ^"^ without other representatives in the islands. 



The small globular snails''' Avith short spires occurring in damp woods 

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

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



^ Sureineti. ^' LiiiiiKcidif. ^" LinnKca oalnifioiix. ^^ Liinncea hinnininis. ^- Ancyliis sliarpi. 



^^ Melaniidfc. >* Melnuin. ''■' Mehtnia man ten. sis. i" j/c/ajua iiewcombia. 



1" Tiviparus chiiiesis. ^^ Tin/iaridce. ^^ Helicinidce. 



