STOMATELLID^. 311 



Shell ear-shaped, regular ; spire small ; aperture oblong, very 

 large and oblique, nacreous ; lip thin, even-edged. Operculum 

 circular, horny, multispiral. On reefs and under stones at low- 

 water. 



Stomatia, Helbing. 



Etyvi. — Stoma, the aperture. v 



Distr. — 12 sp. Java, Philippines, Torres Straits, Pacific. 

 Under stones at low-water. — Cuming. Possil : M. d'Orbigny 

 refers to this genus 18 species, ranging from the L. Silurian to 

 the chalk. North America, Europe. 



Shell like Haliotis, but without perforations, their place being 

 occupied by a simple furrow; surface rugose, spirally ridged ; spire 

 small, prominent ; aperture large, oblong, outer margin irregular. 



Animal spiral, too large entirely to enter the shell ; frontal 

 lobes digitated, foot large, tubercular, greatly produced behind, 

 lateral membrane fringed, ending anteriorly on the left side in a 

 fimbriated crest under the e3^e-pedicel, and on the right in a 

 slightly projecting fold or gutter leading to the respiratory 

 cavity. Operculum, none. 



Stomatia, like Harpa and some nudibranchs, has the power 

 of spontaneously throwing off the hind-part of the foot when 

 the animal is irritated, and Gena exhibits the same peculiarity ; 

 specimens in spirits have the foot usually truncated from this 

 cause. Most numerous at the Philippines, on coral reefs, but 

 also found under stones at low-water. 



MiCROTiNA, H. and A. Adams. (Microtis, A. Ad.) Shell sub- 

 orbicular, depressed, spire but slightly developed ; whorls with 

 two small tuberculated ribs ; columellar lip twisted ; aperture 

 transversely oval. No operculum. Animal as in Stomatia, but 

 the foot with a deep anterior fissure for the head, and with the 

 front edge bilobed. 2 sp. Philippines, New Caledonia. 8. tuher- 

 culata, Ads. (Ixxxi, 75). 



NiPHONiA, Adams. Shell like Stomatella, but very thin ; colu- 

 mellar lip internally thickened, and gradually passing into the 

 outer lip. S. pulchella, A. Ad. Japan. 



GENA, Gray. Shell subspiral, oblong, auriform, depressed, 

 smooth or striated ; spire flattened, nearly obsolete ; aperture 

 very large. No operculum. Animal with the front lobes 

 plumose; foot very large, tubercular, posteriorly produced; 

 lateral membrane not fringed, more or less extended, and par- 

 tially covering the shell. 16 sp. Red Sea, Indian Ocean, Phil- 

 ippines, Australia. *S'. striatula, Ads. (Ixxxi, 76). 



Phaneta, H, Adams. 

 Distr. — P. Everetti, H. Adams (Ixxxi, 77, 78). Siniwan River, 

 Borneo ; attached to submerged logs. 



Shell imperforate, trochiform ; few-whorled, the last carinated. 



