I A N T H I N A 



Plate V. 



Species 21. (Fig. 21a and 21 i, Mus. Cuming.) 



Ianthina exigua. lantJi. testa cotiico-iurbinatd, spird 

 elatd, siduris impressis, apice aculd, anfractibus rn- 

 tundatu, concenlrice lamellato-corrugatis, rugis medio 

 sinmtis; intense violaced, pellucidd ; columelld brevi- 

 usctdd, parvm rejlexd ; aperturd parvd, medio emargi- 

 naid. 



The little Ianthina. Shell conically turbinatrd, spire 

 raised, witli the sutures iiuprosscd, sliarp at tlic apex, 

 whorls rounded, concentrically laniellately wi-iuklcd, 

 wrinkles sinuated iu the middle; deep-violet, trans- 

 parent ; columella rather short, but little reflected ; 

 aperture small, notched iu the middle. 



Lamarck, Anim. sans vert. vol. ix. p. 5. 



Hab. Cornwall; Turton. Connemara ; Shuttleworth. 



This little species may be regarded as the British form 

 of Mr. Nuttall's 1. bifida. The surface is similarly 

 wrinkled with fine lamellar ridges, which incline into a 

 sinus in the middle, arising throughout the growth of the 

 shell by the notch iu the aperture ; and the spire is more 

 conically turbinated than iu any other species of the ge- 

 nus. I cannot agree with Forbes and Hanley in quoting 

 /. violacea, De Blainville, and /. nana, Quoy and Gai- 

 mard, as synonyms of /. exigua. It is, however, easier to 

 say what those species are not, than to determine what 

 they are. 



Species 23. (Fig. 32c and iib, Mus. Brit.) 



Ianthina umbilicata. lanth. testa subghboso-ovatd, 

 tenui, pellucidd, spird lurbiaatd, anfractibus convexis, 

 minulissime concenlrice striatis, striis medio in cari- 

 nam sinuatis ; violaced; columelld recld, teuue rejlexd, 

 subumbilicatd. 



The dmbilicated Ianthina. Shell somewhat globosely 

 ovate, thin, transparent, spire turbinated, whorls 

 convex, very minutely eoncentrically striated, strias 

 sinuated iu the middle into a keel ; violet ; columella 

 straight, thinly reflected, slightly umbilicated. 



D'Orbigny, MS. iu Mus. Brit. 



Eab. ? 



This species, of which D'Orbigny's original type is in 

 the British Museum, is much smaller than /. e.vigua. The 

 shell is slightly umbilicated, aud the fine concentric strise 



incline rather to sinuate round the periphery of the last 

 whorl into a keel. 



Species 23. (Fig. 23ff and 234, Mus. Cuming.) 

 Ianthina iricolor. lantk. testd subglobosd, tenuissimd, 

 spird obtuse conicd, plus minus immersd, anfractibus 

 subangustis, rotmidatis, conceyitrice irregulariter pli- 

 cato-striatis, striis medio sinuatis ; pnrpiirascente-vio- 

 laced, pellucido-iridescente ; columelld vix rejlexd, 

 subcontortd ; aperlurd patuld, bast subcanaliculatd. 

 The kainbow-coloueed Ianthina. Shell somewhat 

 globose, very thin, spire obtusely conical, more or 

 less immersed, whorls rather narrow, rounded, con- 

 centrically irregularly plicately striated, striae sinu- 

 ated in the middle ; purple-violet, transparently iri- 

 descent ; columella scarcely reflected, rather twisted ; 

 aperture open, slightly channelled at the base. 

 This species is unquestionably distinct from I. globosa. 

 It is of a lighter and more transparent texture, and is vio- 

 let-tinged throughout, the colour being characterized by a 

 more iridescent hue. The whorls are narrower, less glo- 

 bosely inflated, and the striae of growth are more roughly 

 gathered into folds, inclining to a peripheral sinus. 



Species 24. (Fig. 21« and 2U, Mus. Cuming.) 



Ianthina striolata. lanth. testd globosd, solidiusculd, 

 spird obtuse conicd, plus minus immersd, anfractibus 

 convexis, tumidiuscuUs, spiraliter pecuUariter lineari- 

 sulcatis, sulcis undulatis, valde irregularibus ; violas- 

 cenfe-albd, medio subopacd, nitente ; columella sublati 

 rejlexd, appressd ; aperturd mediocri, huud sinuald. 



The chamfered Ianthina. Shell globose, rather solid, 

 spire obtusely conic, more or less immersed, whorls 

 couve.^, rather swollen, spirally peculiarly linearly 

 grooved, grooves waved, very irregular ; violet-white, 

 somewhat opaque in the middle, shining; columella 

 rather broadly reflected, appressed ; aperture middling, 

 not sinuated. 



Adams and Eeeve, Moll. Voy. Samarang, p. 5-1. pi. 11. 

 f. 9. 



Eab. Pacific Ocean. 



Chiefly distinguished by an irregular waved pattern of 



linear giooving. The shell is of rather a solid texture 



December, 1858. 



