lANTHINA.— Plate I. 



let-white, rather shining, deep-violet beneath ; colu- 

 mella thinly recurved. 



HaO. ? 



Though so very similar in form to the preceding species, 

 there is a depression and indented character about the sur- 

 face of the last whorl which a])pears to be constant. There 

 is no indication of the roseate hue which tinges the aperture 

 and columella alike in all the specimens we have seen of 

 /. roseola. 



Species 3. (Fig. 3 a and 3 b, Mus. Cuming.) 

 Ianthina grandis. lanth. testa subgloboso-turbinatd, 

 apice depressiusculd, anfractibus tumidis, rotundatis, 

 de suturis declwis, ultimo gradatim descendente, obli- 

 que striatis, lineis paucis flexuoso-sulcatis spiraliter 

 decussatis ; intense violaced, prope apicem albicante; 

 columella tenuissime recurvn, delude sinuoso-contortd. 

 The large Ianthina. Shell somewhat globosely tur- 

 binated, rather depressed at the apex, whorls swollen, 

 rounded, sloping from the sutures, the last whorl gra- 

 dually descending, obliquely striated, decussated spi- 

 rally with a few flexuously grooved lines; deep-violet, 

 whitish near the apex; columella very thinly re- 

 cui-ved, then sinuously twisted. 



Hab. ? 



This fine species may probably be the exotic represen- 

 tative of our British /. communis, resembling it both in 

 form and in intensity of colour. The whorls slope more from 

 the sutures, and the last one descends more than usually 

 below the previous whorl. The surface is moreover cha- 

 racterized by a distinct pattern of flexuous linear grooving. 



Species 4. (Fig. 4 a and 4 b, Mus. Cuming.) 

 Ianthina casta. lanth. testa depresso-turbinatd, an- 

 fractibus late declivibus, deinde subanguste rotundatis, 

 striis tenuibus impressis undique cingulatis ; purpu- 



rascente-violaced, versus apicem cceruleo-albicante ; colu- 

 mella arcuatd, rejlexd, aperturd transversa, medio sub- 

 sinuatd. 



The chaste Ianthina. Shell deprcssly turbinated, 

 whorls widely sloping, then narrowly rounded, en- 

 circled throughout with fine impressed stria; ; pur- 

 plish-violet, bluish-white towards the apex ; colu- 

 mella arched, reflected, aperture transverse, slightly 

 sinuated in the middle. 



ffab. ? 



Distinguished by a more than usually depressed form, 

 in which the striae of growth are less conspicuously pli- 

 cated, whilst the spiral impressed striae, though minute, 

 are numerous and well defined. 



Species 5. (Fig. 5 a and 5 b, Mus. Cuming.) 

 Ianthina communis. lanth. testa depresso-semiglobosd, 

 subtus planulaid, anfractibus declivi-convexis, subrude 

 decussatim striatis; supra albicante, infra purpuras- 

 cente-violaced, circa columellam albicante ; columella 

 subcontorto-reflexd, aperturd transversa, medio paulo 

 sinuatd. 

 The common Ianthina. Shell depressly semiglobose, 

 flattish beneath, whorls slopingly convex, rather 

 rudely decussately striated ; white above, purplish- 

 violet below, white round the columella; columella 

 rather twistedly reflected, aperture transverse, a little 

 sinuated in the middle. 

 Lamarck, Anim. sans vert. vol. ix. p. 4. 

 Helix ianthina, Linnaeus. 



Ianthina bicolor, Menke. 

 Ianthina penieephala, Peron. 

 Hab. Mediterraniau and Atlantic. 



This species is distinct from I. fragilis of the West 

 Indies and Mazatlan though nearly related to it. The spe- 

 cimen here figured was captured by Mr. Cuming in the 

 Atlantic. 



