DIONE. 



Plate II. 



Species 6. (Fig. 6 a, Mus. Cuming.) 



DiONE SEMISULC.\T.\. DloH. testd suiioblotiffo-ovnld, gib- 

 boumcidd, laded, violaceo-cinereo variegatd, lalere 

 ])odico subaltenuato, Iccvigato, anti.co roiundalo, con- 

 centrice regidariter sulcato. 



The H.\LF-GiioovED DiONE. Shell rather oblong-ovate, 

 somewhat gibbous, cream-coloured, variegated with 

 violet-ash, posterior side rather attenuated, smooth, 

 anterior rounded, concentrically regularly grooved. 



Ogtiierea sem'mdcata, Sowerby, Thes. Conch, p. 624-. 

 pi. l;51. f. 83. 

 Bione florid a, var., Deshayes. 



Ilah. Australia. 



M. Deshayes considers this species a variety of B. flo- 

 rida. If so, it is a very distinct form of it, more gibbous, 

 and attenuated posteriorly. 



It will be oljserved that the numbering of the tigures in 

 this plate, owing to some confusion of the lithographer and 

 carelessness of the author, does not agree with the num- 

 bering of the species. 



Species 7. (Fig. 6 b, Mus. Cuming.) 



DiONE II.\GENO"WI. BioH. testd siiblrigono-cordaid, com- 

 pressd, fuli'c-spadiced, fuscescente tiiictd et interrupte 

 radiatd, coiice/itrice plkato-sulcatd, latere postico suh- 

 obliquo, violaceo marginato, lunula et area ligamenti 

 castaiieo strigatis. 



Hagenow's DioNE. Shell somewhat triangularly cor- 

 date, compressed, fulvous-fawn, tinged and inter- 

 ruptedly rayed with pale-brown, concentrically pli- 

 cately grooved, posterior side rather oblique, edged 

 with violet, lunule and ligamentary area streaked 

 with chestnut. 



Cytherea Hageiiowi, Dunker, Zeitschr. fiir ilalak. 1848, 

 p. 184. 



Cgtlierea spathulata, Sowerby. 

 Bione Ilagenoici, Gray. 



Hab. Kcd Sea. 



The most characteristic features in the painting of this 



species are its dark-violet posterior margin and the bokl 

 chestnut zigzag streaks of the lunule and posterior area. 



Species 8. (Fig. 6 c and 8 a, b, Mus. Cuming.) 



DioNE IJIPAR. Bion. testa oblongo-ovali, crassiusculd, gib- 

 bosd, lavigatd, nitente, albidd, violaceo-cinereo ant 

 fusco varii radiatd, fasciatd et maculatd, latere postico 

 lavigato, antico concentrici regulariler sulcato. 



The UNEVEN Dione. Shell oblong-oval, rather thick, 

 gibbous, smooth, shining, whitish, variously rayed, 

 banded, and spotted with violet-ash or brown, pos- 

 terior side smooth, anterior concentrically regularly 

 grooved. 



Ci/tliereaimpar, Lamarck, Anim. sans vert. vol. vi. p. 304. 

 Bione in/par, Deshayes. 



Ilab. Swan Kiver. 



This very beautifully painted porcelain-like shell be- 

 longs to the same well-marked type as B.florida and semi- 

 sulcata, in which the shell is prominently concentrically 

 grooved on the anterior side only. 



Species 9. (Fig. 7 and 'J, ilus. Cuming.) 



Dione costata. Bion. testd ovatd, versus marginein sub- 

 prod uctd, turgida, albidd vet spadiced, fuscescente in- 

 terrupte exiliter radiatd, ad marginem scepe nigricante- 

 violaced, concentrici undiipie dense plicalo-costald. 



The ribbed Dione. Shell ovate, somewhat produced 

 towards the margin, swollen, white or fawn-colour, 

 faintly interruptedly rayed with light-brown, often 

 ilark-violet at the margin, concentrically densely pli- 

 cately ribbed throughout. 



Venus costata, Chemnitz, Conch. Cal). vol. ii. pi. 236. 

 pi. 303. f. 1975. 

 Bione costata, Deshayes. 



Hab. I'hilippiue Islands ; Cuming. Swan River. 



This very fine species partakes very much of the cha- 

 racters of the old Bione Ergcina, but they are perfectly 

 distinct. 



August, 1803. 



