OF MOLLUSCA. 19 



rapidly enlarging ; mouth ovate ; inner lip smooth ; pj„ iq # 



canal open, bent up. Proboscis rather short, thick, operculum of itapana. 

 Teeth 1-1*1; central broad, three-lobed ; lateral 

 kneed, simple, apex incurved. Operculum ovate ; 

 nucleus on the middle of the outer edge (fig. 10). 



1. R. Bezoar. 



2. R. Rapa. (Operculum, Voy. Venus, t. 7. f. 2.) 



3. R. xanthostoma. 



4. R. cassiformis, t. 87 a. f. 8. 



5. R. crassilabrum, t. 87 a. f. 2, t. 89. f. 4. 



6. R. ricinuloides, t. 7. f. 5. 



7. R. kiosquiformis, t. 87 a. f. 6. 



8. R. imperialis. 



9. R. saccellum. 



Rhizochilus. — A Rapana that lives on Antipathes, and at 

 certain periods of its life closes its shell with a calcareous secretion, 

 and permanently fixes itself to the coral, where it eventually dies. 

 See Gray, Ann. fy Mag. Nat. Hist. Dec. 1851, 477; Adams, Gen. 

 Shells, t. 14. f. 5. 



2. VlTULARIA. 



Shell fusiform ; whorls with several angular varices ; mouth trian- 

 gular, elongate ; canal moderate ; outer lip toothed within. Oper- 

 culum horny, oblong ; nucleus on the middle of the outer edge. 



1. V. miliaris. 



2. V. salebrosa. 



3. V. abbreviata. 



4. V. fiscellum. 



In Vitularia fiscellum the lingual membrane is broad. Teeth 1*1-1, 

 brown ; the central with a long, transverse, central tooth, and a 

 smaller one on each side ; lateral hamate, curved, simple, acute. 

 Operculum oblong, rounded at each end ; nucleus linear, on the 

 front edge of the outer margin. 



3. Chorus. 



Shell top-shaped ; spire short ; whorls smooth, rapidly enlarging ; 

 mouth ovate ; outer lip with a strong tooth in front ; inner lip 

 smooth ; canal wide behind, tapering, open. Operculum horny, 

 ovate ; nucleus elongate, external. 



1. C. giganteus. 



4. CUMA. 



Shell fusiform, solid, spirally striated ; spire conical ; mouth 

 ovate ; outer lip crenated ; inner lip with a strong, rather oblique 

 ridge. Operculum ovate, blunt ; nucleus elongate, external, un- 

 equal. 



1. C. sulcata, Swains. 



( 2 



