OF MOLLUSCA. 103 



c. Aperture ovate, truncate in front. 



6. Gyrostoma. 



Shell ovate, turrited, grooved ; mouth oblong ; inner lip thickened, 

 callous behind ; outer thin, with a deep posterior fissure ; mouth 

 ovate, subtruncate in front. Operculum half-ovate, subspiral. — 

 Adams, Gen. Moll. t. 32. f. 4. 



1. G. ovoideum. 



7. Hemisinus. 



Shell ovate, turrited, smooth ; mouth ovate, contracted, produced 

 and truncated in front ; outer lip simple, crenated. Operculum 

 half-ovate, subspiral. — Adams, Gen. Moll. t. 32. f. 2. 



1. H. lineolatus. 



d. Aperture of shell with a distinct notch in front. 



8. Vibex. 



Shell turrited ; whorls costate, tuberculated ; mouth subcircular, 

 produced, and broadly channeled in front ; outer lip thin, sinuous. 

 Operculum half-ovate, subspiral. — Adams, Gen. Moll. t. 32. f. 3. 



1. V. aurita, t. 54. f. 8. 



2. V. Owenii, t. 54. f. 1. 



3. V. celebensis, t. 55. f. 4. 



9. Faunus. 



Shell turrited, acute ; whorls flat ; lips thick, outer dilated, sinu- 

 ated behind. Operculum half-ovate, subspiral. — Adams, Gen. Moll. 

 t. 32. f. 9. 

 1. F. ater, t. 55. f. 1. 



Lingual membrane of Faunus ater elongate, transparent. Teeth 

 3 * 1 • 3, very transparent ; central rather far apart ; apex recurved, 



Fig. 53. — Teeth of Faunus ater. 



five or seven-toothed ; the central lobe broad, rounded, the lateral 

 small, rounded. Lateral teeth: inner oblong, inner part of apex 

 recurved, lobed like central tooth ; two outer elongate, very slender, 

 subulate, nearly equal, curved at the end (fig. 53). 



10. Melanopsis. 

 Shell ovate; spire conic, short, often plicate mouth elongate, 



