lANTHIA.— Plate V. 



for this genus, shining opaque-white, tinged with violet of 

 a peculiarly delicate hue. There is no sinus in the aper- 

 ture, and consequently no spiral sinuation of the stris of 

 growth on the periphery. 



Species 25. (Vig. 25 a and 25 b, Mas. Cuming.) 

 Ianthina bifida, laiiih. testa turbinatd, spird acumi- 

 nato-conicd, anfractibm rotundalk, subangustu, con- 

 centrice dense lamellato-sfriatis, striis medio perob- 

 Uque iinuatis; intense violaced ; columella lenue re- 

 Jlexd, arcuatd; aperturd pared, enormiter emargi- 

 natd. 



The bifid Ianthina. Shell turbinated, spire acumi- 

 nately conic, whorls rounded, rather narrow, concen- 

 trically densely lamellately striated, strise very ob- 

 liquely sinuated in the middle ; deep-violet ; colu- 

 mella thinly reflected, arched; aperture small, enor- 

 mously notched. 



Ncttall, Jay's Catalogue of Shells, p. 68. 



Bob. Pacific Ocean (Sandwich Islands) ; Nuttall. 



The densely set lamellar strise are less conspicuously 



wrinkled in this species than in its congener /. exigua. 



Its principal characteristic is the enormous notch in the 



aperture, which gives the lip a bifid structure. 



